I literally just doubled my DPS from 3000 to 6000, in Act I Hell, for just 22K. I'm a Diablo noob and Hell was giving me trouble already so this should help significantly.
The trick? Reduced level requirement on weapons. Once you hit the high 40s or low 50s, hit the AH and run a search for weapons lvl range 59-60, with one of the search parameters "reduced level requirement = 10". This will show you lvl 60 weapons that are equippable by a lvl 50 character.
So I replaced a 200 DPS 2H with a 400 DPS 2H, just like that.
My new weapon isn't actually very good. The affixes are weak, DPS would be poor (for level 60), etc. It's just very very OP compared to what a lvl 50 char can normally expect to see. If you want to spend 50K, 100K... whatever you limit is, you can find better and better Reduced LVL Req. weapons this way with better and better affixes. I didn't care enough to double my price... I'm happy with 2X the DPS to smooth out Hell.