how much does it cost, more or less to fix a egr valve that is stuck or the pvc valve.

Pcv-- couple of dollars. Egr on the other hand could be much more 50- 100 just a guess. Might just try cleaning egr first carbon build up might be all that's keeping it stuck open. Pcv remove it and give it a shake. If you hear what's sounds like a ball bearing banging around in it it's ok. But if you don't hear anything then it's bad.

Just keep in mind these are just possible causes to this sort of issue

Also might have the alternator checked (most national brand auto parts stores can do this) and give the battery posts a cleaning. If you have any charging system weakness it could be part of the problem.