To give some perspective, I will place some screen shots of money spent with them vs money earned through them. Remember, I would have kept on purchasing online from them anyway, even if I was not aware of their affiliate program. Finding out about the rewards was only a great bonus.
Money I spent so far on Kalahari products (click to enlarge):

A total of R4560.06 spent at Kalahari from 2006 to 2009.
What Kalahari paid out to me so far, from November 2008 to January 2009:

And lastly my unpaid balance Kalahari still needs to pay out, presumably early in February 2009:

You can average these payments out over 5 months since I got paid, but in all fairness, it takes about a month or two to get things rolling, depending of your website's traffic and your users / reader getting used to it, so lets average it out over 7 months.
A total of R2365.33 conservatively averaging to R337.90 per month. If you do average it out over 5 months, it gives me R473.07 per month.
If you subtract the total earned from the total spent at Kalahari I get a total of R2194.73. More than a 50% discount!
I suspect that Kalahari store cookies on people's web browsers, so that when they click to buy something through one of your links for the first time, they become your "customer" for quite a considerable time.
It is definitely worth your while to sign up and try it out for yourself. For the next post, I will probably share some info with you on the less profitable pay-per-click affiliates such as AdSense and Synergy before moving on to other online shops such as Take2, Loot and PC Mall. All four of these are very new to me and I hardly have any stats or money to show for them. I will however put it up here with some screen shots and frequently update on them to see if there is any improvement at all. I would like to do a similar post to this one for Take2, as this is the place on the internet where most my cash went when I still owned a DVD rental shop. I hope I will have some figures ready for you. For now I am on R0 earning.
Until next time...