Aerobatics can be addictive but, provided that the exercise area isn't too far away, is relatively cheap since your flights are normally relatively short (but plentiful).
Half an hour hanging upside down and experiencing all sort of weird g forces, combined with the mental and physical effort of flying the aircraft truly in 3D is usually enough for me. Add the transit to the practice area (which is about 10 minutes either way) and some taxitime means that my total flight duration is normally about one hour. The flights that were done as part of the aeros competition a few weeks ago were typically 15-20 minutes from engine start to engine stop.
If you get a little experience though, you will also start to fly some of the more exotic types compared to the average spamcan. For starters that means getting a tailwheel endorsement. Plus, a lot of the more capable aerobatics aircraft cannot be rented easily so you'll need to buy a share in a group.