Rebecca,
It is tough to find inexpensive outings. First, try to find a group of mom friends to hang out with for playdates for the kids/coffee dates for the moms. Try Meetup.com and then Lancaster County Mom's Group. I made some of my best mom friends through that group, although anymore, my son is in school part time and we don't need the play groups so much anymore.
When it is nice, I pack lunch and go to the park for the day. That is free...we would eat lunch anyway and it feels special to take a picnic blanket enjoy the outdoors, explore a park. The mom's group often meets at parks at least once a week over the warm months, or since you are new to the area, correspond by email with some moms from western Lancaster (maybe post for email friends on here) and when you find a few that you feel you have something in common with, start meeting at a park for playdates.
We save quarters and go to:
-Jimmy Macks (route 462 west, over the bridge then not far past Wrightsville) for the arcade, kiddie rides, playground and ice cream.
-Chuckie E Cheese, just to play, we don't eat there, or maybe kids will have a slice of pizza
-playground at Park City downstairs at the food court. FREE
-KidsEscape in New Holland, it's a drive for you, but it's only $5 per kid, I think for 2 hours at the huge indoor playground and they have coupons online.
Also you could trade off hosting play dates with another mom and just snacks and an activity for the kids...could be finger painting, play dough, seasonal crafts, of just playing together for an hour or two.
Hands on House is good, but it is between $5 and $10 per kid. We found it more economical to become members and then we went at least once every week or two.
Hang in there, in 3 years they'll all be in school!
L.