Speak to Bubbawoo, he is the best person to speak to about real estate
http://www.polishforums.com/index.php?action=userinfo&user=846 You can purchase a holiday home in Poland no problem as far as I know.
Cheap is relative to what you want to have; in the Bieszczady Mountains prices are still quiet cheap but prices are rising and I would say it's a good investment for the future, but I am no expert just personal opinion.
Another place is the Mazury Lake District, which is a personal favourite of mine and is so peaceful if you find the right place. I am English myself and my wife and I are in the process of buying a holiday home in this region at the moment, but in our case it is easier as my wife is Polish and we live here.
As to Polish people not liking you, I think it would be more a case of not liking your Business because of competition rather than not liking you for your nationality, but this is just a guess.
As I said speak to bubbawoo, as he might be better placed to advise you :O)