Most provide decent lodging, two big meals a day and the guiding. Some will pick you up at the airport if you're flying in. It's cheaper if two or more hunters go per guide versus one guide per person ($$$$). I went on an unguided hunt in Wyoming years ago and the "son" of the rancher field dressed my buck for me and helped me cape it out. I've never went on a guided hunt so I don't know what you tip them or any of that.
Search the state you'll be hunting for guides and find the ones with websites to browse. That's a place to start....
Check in with the Outfitters and Guides Association in the state you plan to hunt. All reputable outfitters will be members and the Association will have good info. Then call around and ask for refrences. The good outfitters will be glad to provide you with contacts from previous clients.