Asking Relatives to Pitch in Money for Thanksgiving

This year, many of us are making Thanksgiving dinner for a lot of family and friends. On average around 5-15 people will be there.

The economy sucks, and Thanksgiving is expensive. Some have already dropped a lot of dough on expensive flights, and don't feel like paying for all the food.

So instead of asking everyone to bring a side dish, what about ask them each to pitch in $10 toward the cost of the food. And they're all cool with it?

Some have already started the tradition a few years ago.

Is it rude to ask people to give money for Thanksgiving dinner? Since you have to feed so many people, isn't $10 per person reasonable? Or is it tacky?