198 reviews
  • Fantastic add-on, works in the background and is completely unobtrusive. You forget it's there until you buy something on-line. It saved me £51 on a Sony E-reader!
  • it really doesnt work for me. slows browsr down to a CRAWL and there is not real coverage so most of the time so no real offers and oftentimes the difference or saving is about 2c. Which sucks. also it doesn't consider shipping or any other information.
  • Works well with popular items, but not so well with unpopular items.

    I use it (unashamedly) with our extension to save even more money: cashbackautomator.com.
  • Working perfectly for me on tons of sites! Saved me over £13 on a PS3 game and over £20 on a DVD boxset, without all that comparison legwork.
    Discreet too, nice!
  • I really wanted this to work but it just does not. It is always gray no matter which site I am on and I am on Amazon all the time looking at very popular items like games, books and simple kitchen items. This has not once shown me a price option. Also I cannot get into the add-on options for this add-on, is it possible? I will leave it just in case it starts to work like I said I really would like it to work. Thanks.
  • The worst thing about this extension is that when it runs, it locks up Firefox completely, and it can take quite a while to run. Second, its selection of retailers ("over 50") is quite small; this is no substitute for a search engine. Third, it doesn't count shipping charges, which throws off its comparisons, making many of them inaccurate.
  • Awesome extension, absolutely necessary when buying textbooks. It would be nice if in the future InvisibleHand compared prices for new and used (eg. on Amazon) products and account for shipping prices.
  • Excellent! It keeps saving me money

    Every time I shop for something, it either finds another store which sells it for less, or it reassures me that I've already got the lowest price. It reminds me a little of that Arthur C Clarke quote about how any sufficiently new technology is "indistinguishable from magic"

    I guess it's not actual magic, but it's very very clever. I'll definitely be keeping it.
  • I have tried installing this multiple times in older versions of FireFox and in 3.5.2 which I am currently using on OS X 10.4.11, and it never works. I have never had a price alert come up, and despite the arrow blinking, every time I click on it the pop down bar just says "Invisible Hand doesn't have any suggestions for this page." I have tried it on pages that other people using this addon have had success with.
    Please accept our apologies. We had a few outages on our US servers earlier in the week which prevented US users from seeing notifications. The problem has been addressed and things should be back to normal. UK users were unaffected.
  • Works perfectly, however it cripples firefox while it searches. If I open 4 tabs to amazon.co.uk or scan.co.uk or ANY site selling stuff, it grinds to a halt, I assume while it searches. Sometimes Firefox is unusable for about 20 seconds and it happens EVERYTIME.
  • I agree with jswagner's comments about the screen jumping around as the bar is re-drawn; hopefully that is something which will be fixed soon, as it becomes annoying.

    Other than that, it's great! CHEEZEY MARK, you must be doing something wrong, because it works perfectly well with UK prices.
    Thanks for the feedback. We've noticed that some products cause the price notification to 'flicker' if the product is available from many different retailers.

    We're currently working on a fix for the issue, and we'll be deploying it in version 1.6 very soon.
  • When the addon finds hits for multiple vendors, it redraws the popup bar several times in a row (which scrolls the browser window). I was looking at an external hard drive and couldn't interact with the page because IH was jumping the page around so much! I had to wait until it was finished just to find out that I was already looking at the best price.

    A better approach to this would might be to simply light up the status bar icon and let users click it to display results (similar to how TwitterFox reports new tweets by lighting up and displaying a super tiny notification), rather than interfere with the user's browsing experience.

    Otherwise, fantastic addon!
  • Doesn't work with UK prices.
  • Looks like they use Amazon AWS for hosting. Nothing wrong with that, and no conflict there. Probably a better deal than dedicated hosting.

    Please do your research before shouting foul play after a simple whois search.
  • @fernginger

    Before you go all "vigilante justice" on this add-on, get your facts straight. This is NOT an Amazon product. Your amateur sleuthing revealed an IP address of, but that's for Amazon Web Services. Yes, the same arm of Amazon that provides hosting services for sites.

    Obviously, the company behind this add-on is hosting their page using this technology, but that's hardly a conflict of interests.

    And no, this is not an Amazon product. Double check your facts before your next smear campaign.

    Me? I like the add-on quite a bit and find it very useful, but really wish it could show shipping info (like enter your zip and preferred shipment method into the add-on preferences). Other than that, I haven't noticed any issues with the results.
  • I like the idea. However since it can't take rebates and shipping and handling in to account (and not by the fault of the addon -- it really is too complex) the information is too incomplete to be useful to me.

    My main gripe is that the info bar pops up and disappears with each new price it finds... "best price out of 2...4...5..6". And at least on this machine (I've yet to try it at home) I can easily notice the lag when it's doing its work.

    (FF 3.5.2. + Vista Enterprise 32 bit)
  • A genuinely useful addon that I intend to keep which has already saved me money!
  • Awesome, really neat & tidy add on that continues to get better.
  • +++ Very discreet. Handy links to other retailers with the item I searched for.

    - - - I looked for a selection of things I've bought lately, and it only had information on about half of them.

    All in all, I'm going to keep it, as it doesn't bug when it has nothing to say and it can be helpful when it has information on a product.
  • This addon is excellent and to be honest, one of the best addons that I have used in a long time. This addon is discrete, you don't know it's there and even when it finds results, it isn't in your face. There are a lot of retailers that are available so finding prices is never a fight. I would recommend this to anyone that buys items online.
  • -edit-
    Thanks for the feedback. We've located the issue, fixed it, and released version 1.1. The new version should avoid the conflicts you experienced with other add-ons.
  • I had to return to amend my earlier comments. I eventually ran into similar troubles with other extensions, particularly using the 3.5 RCs. It is now clear that Personal Menu is the addon that isn't playing nice, and not InvisibleHand. Being the first time I saw the problem, I did not consider that it could have been a longtime extension already installed. Mea culpa.

    Anyway, I reinstalled InvisibleHand, and it's working just fine now.

    And thank you to the developer for responding to my earlier comment. Looking forward to continued development.
    Thanks for the feedback. We've replicated the problem and we're now working on a fix which we'll deploy asap.
  • Probably the best price comparison I’ve seen. I like the way it’s only visible when it’s found a bargain on the product you’re browsing. You don’t even know it’s there until it finds a better price. The price comparisons are very good: no bad links or out-of-date prices. It seems to compare all the ‘big’ retailers like Amazon, Newegg and BestBuy, although it wouldn’t hurt for it to do more of the smaller ones too. Pros: Accurate. Fast. No pop-ups Cons: Some of the smaller stores aren’t supported.