The most I spent on a photograph was $1000. It was a Rolfe Horn. Dusk, Izumo Japan. I knew I was "closing" out that price range, (an immediate profit I rationalized to myself) and it now goes for $4000. I bought it because I loved it (and at the time had the money). I have also bought some photos here on APUG. I have a couple of Alex Hawley's prints, and I contacted and bought one from Andre Avillez even though he wasn't openly trying to sell it. I have also found some masterpieces in the group print exchanges. I recommend that everyone join those. another apuger here that I own a few prints is Bill Schwab, they are wonderful and I only wish I had more of them.
Everything that I have read about collecting says that you should love what you buy. I love everything that I have bought.