To buy enough items to make it through act 1 and hopefully act 2 Inferno. I'm doing about 12k dps and I have about 19k hit points... I'm over 2 attacks per second. I have 200+ resists But I feel like I need to scrap all my gear and start over as I can't even handle act 1
For Act 1 you should get more @ around 350-400 try using One With Everything passive and you should be able to get few upgrades dirty cheap. 500k should be enough to fully gear up for it (including some good weapon and shield). I mention weapon and shield because it is cheaper and safer choice.
Act 2 is another story and without ~30k hp + 500+ @ + ~4-5k armor you will be their punching 1-shotting bag.
Item prices are crazy right now due to recent RMAH opening so it can be difficult to get good items cheap.
But you should be able to get good enough armor pieces at around 200-300k per one.
Good weapon will probably cost you around 600k or easy mode ias+loh/sox one at 1.5-3m and ~500k for usable gem.
I cleared act2 with 23k hp,600 all res, 9.5k dps, 5k armor, 800ish LoH, 1.8 attacks per second (before whatever buffs I might have). Belial was rough since his normal swings one-shotted me from time to time. I think I managed most elite packs after the Kulle head quests (last set of upgrades).
The weapon cost me just under 400k, the gem in it is just over 300k to craft on your own. None of the other pieces bought were over 150k, most were sub-50k. Some of the self-found pieces are probably more expensive however. String of Ears was probably 400k when I think about it, but I'm thinking I would be better off with a rare anyway.