Alison,
People are different - my grandparents were very different from some of the nice people listed here! One set is remote - they lived approximately 10 miles from our house, and would have nothing to do with us. To date, after 40 years of marriage, they have not set foot in my parent's house. Shame on them, yes.
My other grandparents, well, we visited them a lot, and they visited us a lot, but babysitting really didn't happen. My grampy sat for me once when I was very sick (my parents didn't believe in hospitals unless you were dying or close to it :) but that is all I ever remember. My Nana died when I was five.
My parents will come to visit (6 hours travel time), but they will not stay with my son on their own. One reason is he is still breastfed (somewhere, between my husband and parents, they all believe that they can't 'watch him' because of this!) I am teaching him to sip from a cup (my glass, because we actually don't have a bpa-free sippy cup at the moment, and can't FIND one). He is doing fine, I am doing fine, and if we don't see a movie, it is not the end of the world. My other half watches enough videos for me and the rest of the clan as it is.
My mother-in-law won't come visit. She developed an allergy to the dog years ago. We also don't see eye-to-eye on discipline/ punishment. She believes in spanking. I do not. We have gone around and around on this issue, and that was long before I ever became pregnant. I think we're both happy with her choices. She has 24 other grands and great-grands, she's not worried about our few trips (again over 7 hours) to visit. She is a nice, lovely woman to visit, and we are happy with that.
I'm sure after a second year of being cooped up by myself, I'll have a very different opinion, but for now, it is what it is - we can't afford a sitter, and we won't wear out our emergency sitter with a movie night. She's great! but she has her own family and life.
So, best of everything, it is what it is - if it is gas money, then let them know that is why they don't get to see their grandkids; if it is time, let them know. They are fully capable of communicating their schedule(s) with you, and you can slot them where they fit. Smile, and make the most of what you can with what you have. Good luck with that!
I find that people use the word never, it's because they have a very good reason - theirs.
Good luck,
M.