the cheaper brands are tenda and trendnet both have there pros and cons
i recommend tenda its cheap and just works (R500 or so with wifi) although i must admit i hate there latest model w150d so if you can get a previous one then go for it else just update the firmware straight out the box.
oh billion is also very good but the reason i stick with the tenda's is because they come standard with lightning protection (6000v me thinks)
have a look at the brands and decide whats best for you, my money is on the tenda
There is also TP-Link which many here are quite happy with.
Derail: I'm wanting to go the other way, is there an expensive ADSL router with Wifi that is worth paying a premium for. Router is in a room with thick walls that is killing the signal in the rest of the house (and no, I can't move it somewhere else without a huge hassle)
I've had the same basic D-Link ADSL Modem for about 4 years - the 2500u.
You can get them for around R200 or less. Been extremely stable up to now; subsequently attached a TP-Link TL-WR841ND Wireless router to it, and both work well together.
The D-Link 2750u is a wireless modem/router in one, approx R600, last time I priced them - have read conflicting views on them in this / other forums, so it's a case of take your pick, and hope for the best !
I have had a netgear DGN2200 for 2 years and while it was not the cheapest at just under R1000 it has given me great service. It seems to have lightning protection in it as I have had a couple of strikes at the house and it has survived while other devices have not.
While Pinetown is not as bad as the Highveld for lightning, you do get some great electrical activity.