the best because of indispensable "Last 10 Hosts" feature Rated 5 out of 5 stars
I just read thru all the cookie managers / helper addons and tried a few. This is the ONLY one i found which has "Last 10 Hosts" feature. That is simply indispensable when it comes to what i need--turning off ALL cookies except for a very few (maybe 10) sites (banking, webmail(zoho), certain highly trusted providers. I let facebook set cookies too, even tho i dont trust them at all :(
But, often a new site i want to trust will use a second site to process a transaction. But you are never "on" a page with that second site. The page you're on just goes to it for you to, say, make a sale. But THAT second site needs a cookie. How do you set it? Often it does not show up in History, as History entries are mostly pages you clicked on yourself.
But these hidden sites do (most of the time) show up in Last 10 Hosts. So you if your transaction fails, check Last 10 Hosts and see if one of the blocked hosts looks like it might have been part of the transaction. Allow that host. Then try again. This works for me most of the time, and makes this the most valuable cookie manager addon IMHO.
If that does not work, my other technique is to open the View Cookies, then Allow Cookies Globally, then retry the transaction, then see what cookies were added. There is almost always the hidden, necessary one, plus one or more ad cookies that i then delete.