I enjoyed my first safari with this company in 2007 before returning in 2010 for a second. I would encourage you to get in touch with Gavin Opie if you are thinking of visiting South Luangwa National Park. He lives on-site and so personally oversees every safari.
"For several years, Chachacha Safaris have been conducting tours to the South Luangwa National Park designed to suit travellers with a more modest budget. In 2007 Jackalberry Safaris proudly began operating as a separate safari company, retaining the ChaChaCha mission to provide independent travellers with quality safaris at low prices. Because we are a small company and wish to remain so, we conduct tours with a maximum of 12 guests. This means that all our clients receive a personalised safari experience, rather than getting "lost in the crowd" which can sometimes happen at the larger lodges. Jackalberry Safaris combine walking safaris, game drives, cultural activities, comfortable accommodation and delicious food while also providing transfers to and from Chipata." http://www.jackalberrysafaris.net/index.html