Regular, non-electric campsites for tents on public land costs around $20 a night and $40 for two nights. Keep in mind that camping at state parks may require an annual park pass for entry, but this depends on the state. A standard electric campsite that accommodates a small tent with enough electricity to charge phones and blow up an air mattress costs $26 for a night and $52 for two nights.
RV campsites can cost anywhere between $25 and $80 per night, depending on certain things like the location and the size of the space.