It's difficult to get hold of the Botswana booking process and fees. You have to contact the relevant concession management and figure it out. Contact details are in the campsite reviews.
South Camp fees we paid for 2 nights at SADC rates: - Camping fees: USD86 - Foreign vehicle entry fee: P525 for both Makgadikgadi Pans and Nxai Pans NP combined. - Conservation and other fees: P380 per day for both of us. Fees are a bit complicated to work out. They only sent totals for the national parks' fee aspects (i.e. not camping fees, all other fees).