Electric or gas?? And what model?
Check out the local clubs in your area. Glow Powered (GAS) planes are not meant to be flown in parks. You will need to join a club and join AMA.
I recommend Glow Powered:
A great start would be the Hobbico Avistar Select. Comes complete almost ready to fly - radio, engine and plane. Tower Hobbies has them for $299.99 and they have a $15 off coupon on the front page.
Extras will run you anywhere from $50 to $150. If you don't like the hobby you could easily sell everything - as long as it is not smashed!!!!