G-Force is another good one to use. Most of the rally cars on a budget that I have seen use them. I've seen them go for about $70 for the latch link, and $110 for cam lock. Those are both for 5 point harness'. I got those prices from
saferacer.com But judging from the prices of some of thier other products, you might be able to find them for cheaper. I'll let you know if I find any more sites that have them.
I would definitely go with cam lock though. For the little extra cost, they are a huge coinvenience. I've sat in and used both, and couldn't see using the latch link ones for everyday use.
*Edit* Link works now.