I just had mine removed back around the beginning of the month. I do not feel any better. Immediately after I felt worse actually--bronchitis I was getting over flared up and such. I had 7 from a young age (am 36 now). So short term, I can tell you I did not feel anything better. I'm hopeful for the future though.
For cost, it cost me somewhere around $250 per tooth, depending on the type of Amalgam and such. There was also an initial visit cost and stuff like that. I think it probably cost me about $2000 altogether for all 7 teeth and the visits and X-rays and such. My insurance covered only a portion, since I used a holistic/biological dentist instead of one in my plan. If you go to a dentist outside of your dental plan, you might first consider getting your X-rays done under your plan and save you a few dollars--take them with you to the Amalgam removal dentist.
I'd love to hear from others if I should expect long term health benefits. At this point I just don't know, but I'm hopeful! I have read good things from others, and I read one study that said something about immune function increasing after about 6 months or so after removal--I think it was something about T cell numbers increasing. My wife had hers removed by the same dentist, and she thinks it helped clear up any remaining sinus issues she had (she said at some point shortly after the removal, she blew out a big glob of nasty mucus and it made her sinuses feel better and more open).
Many say you need to do detox after it for a while to get better, at least from what I've read.
It would be interesting if some studies were done with "healthy people" to see if they have Amalgams when they were children. Also, people who live to an old age--see if there is any correlation to health issues and amalgam.
Those are my thoughts. I'm happy to give you more details about my removal if you need/want them.