Hosting providers like Serverpronto offer amazingly good deals on dedicated servers but the tradeoff is that at $30/month, you only get 256MB of RAM with your server.

With so little memory, the default Apache memory configuration in the Redhat distribution will enter a flaming death spiral of swapping under moderate load.  If you’re in that boat, you should read Optimizing MySQL and Apache for Low Memory Usage by Emergent Properties. 

There are a number of tips, but the most valuable one in my experience was the simplest.  Reduce the default keep-alive timeout from 15 seconds to 2 seconds.  2 seconds is long enough to ensure that a page and all of its resources are fetched in a single TCP connection, but greatly reduces the need to create new Apache workers or queue requests because existing workers are tied up waiting for the keepalive timeout.