A group of us (8 ppl in total) decided to spend some time in Africa - budget style (excluding airfare, of course). We decided on Namibia (before Angelina Jolie put it on the map) and rented in Windhoek (the capital) 4 x 4 SUVs with two tents on the roof.
I cannot remember the exact place we rented from, but there are plenty of places on the web you can research. The cars were comfortable to drive in, with CD players and the tents were also pretty comfortable with built in pads on the bottom. The rental also came with basic camping gear and sleeping bags.
We drove up to Etosha National Park on our own and camped in the park. The campsites are located right by the watering holes which is where all the animals gather since it is so dry elsewhere. (Campsite area and bleachers by watering holes are gated from the animals for protections) We saw just about all the animals you can see both at our campsite, and during our day drives through the parks - lions, a cheeta, elephants, wildebeast, a herd of ostrich crossing our path, zebras, rhinos, and my favorite....the giraffe.
An amazing experience and a rugged way to see Africa independently from the high priced game reserves.