Huge Mongo datasets. How much RAM do I need and how to not get ruined by paying for hosting?

So, I have a what I call huge mongo database which is about 30Gb (about 30 millions documents). I tried to run mongod on the server shared with another application and it was completely slowed down. So I have to look for a dedicated server but have no idea how much RAM do I need.

I understand that I probably need to hav开发者_如何学Goe amount of RAM enough to put all indexes there. But, if I'm correct, it would be about 13Gb of RAM which makes the price for the server very-very expensive (my app isn't making any money yet).

I tried to look into mongoHQ, but their cheapest dedicated plan is $600/month.

Any ideas? Is it really that expensive to host heavy mongo databases like that?

Build your own server and colocate it instead of renting someone's server. You have full control over the hardware, higher startup costs, but lower long-term costs. You are also liable for hardware malfunctions, so watch out for that.