The hosting company I'm talking to said that it would be difficult to manage a VPS without prior experience and training.
IF can't afford a managed VPS, what do I need to learn to manage my own VPS and where can I learn it?
Administering a VPS is similar to administering a regular server. If you have those skill-sets to administer a server, you are already about 80% there. The last 20% are the little caveats that you need to learn about VPSes depending on the infrastructure platform.
e.g. I/O infrastructure, networking etc.