In a radical move to stop the complaints about costing, Vodacom decided to start paying you to use the network, so the more you talk the more credit you'll get.
You can either cash out once per month, or if you wish, let the credit run up and claim a product at the end of every 12 months. If you use about 500 minutes per month, you should be able to claim a new laptop with embedded HSDPA.