I just got a VCR from a second-hand store, it works but after 30 minutes it stops recording/playing.

Is that VCR wearing-out or do I need to get another one?

Need to know more info---
what make?
what features are on it?

Does it have a one-touch-record button?
If it does it may be "stuck" in "on position", the one-touch button is usually set to record in 30 minute segments.

here is a website that might help to fix it:

www.repairfaq.org/sam/vcrfaq.htm

I just bought a new one...that one works better anyhow...

Im sorry ya had problems my friend :(