I thought I read that Monster Bash required licensing from each monster. Maybe it was written in sarcasm and I was dreary eyed. Not sure, but that might be a MB deal delayer, maybe not. Maybe Rick can clear up any licensing that is required for a MB type theme(Warner Brothers?), and the time to process the paperwork/negotiations and have to deal with that part of pinball biz. You give up your hobby when you make it your biz?
As far as the price goes, keep it as low as you can, but still make enough profit to keep rolling out the remakes, cover your family health care, bills, etc, family vacation, new used car, AC fix, kids braces, etc.... Best of Luck!!