I tried to buy wines that I hadn't heard of before (but I also bought one that I had heard of: a Klein Constantia "Vin De Constance", simply because I've liked this wine in the past).
The others I've had have been: a Radford Dale Shiraz, an Observatory Syrah, a Columella Syrah and a Flagstone "Music Room" Cabernet Sauvignon. These ranged in price from about $15 for the Radford Dale through to $30 for the Columella. Generally I have been impressed by all of these, but especially the Radford Dale and Flagstone which were, at wines costing $15, excellent value, and nicely balanced and refined. That said, I am buying a few more bottles of the Columella and Observatory, as they are both excellent. I would doubt that these wines would be easily available outside the UK (the Klein Constantia will, obviously), but if you're in the UK then I believe that Oddbins are the sole importer. Oddbins are excellent for good value wine (I've found so many gems in there).