I don't think it has to be about money, there are plenty of free outtings, for example last weekend there were lots of free dragon dance displays in bigger towns up and down the country.
It's about planning activities with older children, younger children love having granny come to their house and going to granny or grandad's house is a big treat, not so for older children! We try to arrange activities for them with their grandparents now, it doesn't have to cost money but it works better than sitting at home being grilled about "how's school" for hours on end and means they're building memories together.
Obviously you can't do outtings all the time, but make sure there's always something fun planned for some time in the next couple of months too
this applies to parents of older kids too, not just grandparents. We make sure we have some fun outtings planned with the girls in their calendars because day-to-day you don't get the same sort of quality time as you do if you plan something "on their territory" as it were.
Odeon does £2.50 cinema tickets on Sunday mornings. We sometimes do that, although that works better for the 7ish ones, the cheap showings are cartoons so as they get to 9/10 it's not so good.
NEW GAME - ALPHABETICAL groups/bands