That can be expensive with the gas prices as high as they are but, they are family and older people should not be traveling and plus they tend to be more set in their ways. The thing is, this is a family holiday, a time when families come together and laugh and see each other. As a mother of three, if my kids were tight on money, I would GLADLY offer them travel expenses, if they came. I would hope they would have offered that. Anything is possible, cut back on things if that's possible, especially if you have children, I know it's hard. Maybe eat spaghetti or beans for a month and drink water, avoid a restaurant? offer to babysit for someone, or pick up a part time job. If this is already something you do then I would mention to them that you have Christmas coming up and that money is very tight around that Holiday and as much as you wish you could come visit, you just don't have the finances to do so. This is a time when the world is very uncertain, the stock markets are SCARY! The major businesses are going under and asking for help. I can see your point, and I can also see theirs. It's never easy when it comes to family and Holidays, just let them know if it was feasable, there is no where you would rather be. Maybe they will shock you and send the money. Wish you luck.
