$500.00 for 10 Servers. You will be looking at extremly old-hardware for that price range. Celeron 2.0GHz-2.4GHz.

It's possible to get a Pentium 4 2.4-2.6GHz for that price range but that doesn't mean its the best option possible. Since you seem dedicated in a long term relationship with the provider you select, maybe you would want to increase your budget.