starting @ around $4-5/month is not that expensive. It's easily recouped by your EA and then some......If you can't make at least that much per day or two...then you should rethink about trading using EA. No offense.
From my experience 1 vps can run multiple EAs no problem. Just check on the CPU loads if worry. The real problem is how many MT4 or MT5 you can run in 1 VPS. The answer is depending on your VPS option.