Not sure what inexpensive is to you but a friend of ours just had her daughters 5year old party at Galaxy Games and Golf off 70 and Wilson I think? West side area. Anyways, for the pizza party/drinks, cake/ice cream, tokens for the kids to play some games, and the jungle gym thing, it was $12 a head, she had 10 kids including her daughter. So I didn't think that was that bad, they provided everything, cleaned up, and made it care free. Plus the jungle gym was big enough for me to crawl/walk around, so its nice that its bigger than magic mountains. They also offer putt-putt if you think she'd like that.
HTH, dunno what 8 year olds think is cool, lol, mine's only 4 for now.