Is there any way to monitor one process' CPU usage and RAM usage over time on linux? I am trying to change to a cheaper VPS and need to work out what level of CPU and RAM I need!
a simple 'collector' works like this (for a process with the pid '29777'):
to make life easier, you could also use the systat package which includes several means to collect data over time:
pidstat is a very good tool for the cpu part of your question.