Hi Pedro,
I would suggest booking a tour of the
Yellowstone Park as the expertise of a guide will make the experience more enjoyable. Most tour operators offer the accommodation, food, etc as part of the package so, it would be a cost-effective way to save money.
If you are planning to stay longer than a day, then some tour operators even offer other activities such as fishing, horse riding, etc; also as part of the package so, it is worth looking into that.
It is worth mentioning that the Yellowstone Park offers guided
animal tours where you would be able to see spectacular sights such as wolves, bisons, bears, etc.
Hope this helps
VacationBuddy