Do a lot of reading about the type you're considering. There are lots of "type" books out there on the more common types, and type clubs as well. One of the publications I like is Aviation Consumer.
Aviation Consumer
They seem to tell it like it is, and will have lots of information in archives.
What could challenge you are unexpected maintenance requirements - so expect them, by understanding. Doing so is entirely your personal responsibility. A mechanic you could hire might know many of them, but he will not have enough time to explain it all to you from a standing start. Rather, get yourself up to speed first.
There will be a massive jump in price for Cessnas and Pipers now, based upon their being "legacy" or not. The older aircraft are still great planes, and the same to fly as the new ones, but they subject to some parts availability difficulties, and additional inspections (which are entirely reasonable). Your saving in purchase price reflects this. That's not a "don't buy" warning at all, just cautionary - understand what you could be getting into.
Once you are part way into your research, ask your more type specific questions here, there is lots of type specific wisdom and experienc here...