I feel your pain! I am a long-time acne sufferer. I've had it since junior high school. I've gone through lots of dermatologist's products, Proactiv, and drugstore skin care products that really didn't work. I recently started using a combination of Paula's Choice and Alpha Hydrox skincare products (both of which are relatively inexpensive), and my skin looks pretty durn good! The pimples are almost non-existent, but I still have some dark spots from old blemishes. Those are going to take time to fade.
My first question, though: have you seen a dermatologist? It might be a good idea to rule out any underlying medical problem that could be contributing to your skin issues.