I rode cross-country in a group ranging from 8-10 riders, ate most breakfasts in camp, lunch in town at diners, Subways, etc, and rarely took advantage of the potential for group meals and ate most dinners at restaurants as well.

The daily budget for the 9 weeks we were out came to about $25, which included 2 hotels paid for (which were not necessary--camping every single night is entirely possible) and another hand full of campgrounds. Most nights were spent in town parks or other free camping spots.

I would recommend at least carrying a small alcohol stove for the option of cooking when away from town or when the options for a good meal are limited. You may also find cooking as a group much cheaper, healthier and more flexible.

Either way, hammering out a budget (and, if you're limited to a tight one, coming to terms with sticking to it--whatever sacrifices that entails) before beginning your trip is a great idea. "It's just one night in a hotel..." can quickly send you down a slippery slope.