The only thing that I've found actually effective is laser treatments. I think prescription Retin-A (or whatever it is) creams cost just about as much anyway.
My insurance covers Retin-A and there is a generic now. My skin is too sensitive for it but I have gotten it in the past.
I love Paula's Choice, I'd try the recommendation above and maybe even the Vitamin C serum.
I've found the best thing for me is a lactic acid peel, I do them at home but only in the fall/winter months.
I am trying the Murad dark spot and pigmentation corrector. The reviews are pretty great. I have two decent size ones on my face that make me pretty self conscious.