Get a phantom instead of a promaster and play with that. Congradulations, your cost to play for a day went down to 200-300 rounds, entry, and 12 grams.
(and if i didnt convince you
)
I agree with the lack of funds being the main issue. If you cant get more money, maybe you can settle for playing every other weekend instead. The best situation is if you get her to at least try paintball (use the term marker to get around the whole "guns" stereotype.