I'm not very sure about the bump scars. I think it helps because when you massage the cream on your face to create the microdermabrasion effect, the crystals will flatten the bumps. How effective it is depends on the type of bumps and whether they are very big and hard. I had some very stubborn, small, hard white bumps on my cheeks (not sure if they were clogged pores or what not), the Epidermx got rid of them in one use. Of course it'll take much longer if they are scars.
I've been using it for about 7 months. I use it twice a week and the jar (2oz) still has a third left. You only need to use a tiny amount each time. I don't know where you can get it cheaper. I got mine at Goldport Beauty and it was free shipping.