Cobolt blues come around every now and then, someone did breed and get some slings out but I think they have all been sold out. As for a price it depends on the person selling them, they can start from R120 for a sling.
http://www.mrtarantula.co.za/ is selling H.lividum for R400.00, for 1-2cm spider. He is trusted person and has a pet shop so you can also go directly to him. The owner is Jozua.
As cascade said, Mr. Tarantula seems to be a safe bet when buying and his prices are reasonable, you can also google uncle Tarantula, Robbie is his name, but his prices seem a bit steep these days.
"I hold that the more helpless a creature, the more entitled it is to protection by man from the cruelty of man"