It's not how much you pay, it's what you get I guess is what we're really trying to get across. To me the the $100 comment is maybe misleading a little. For $135 you can get a used rnc. that's pretty much the $100 range, and it's a great compressor. You can get used dbx units for that range too if you're lucky. And some people charge as much as $150 for 3630s, unmodded even. It's funny how pricing works - it really has very little to do with the true value of a product.There are good behringer compressors for $100, actually quite useful.
If you get a 3630 for a little less than $100 you can spend another $50 or $100 upgrading it's components with the well known fixes to it's design. That will give you a compressor that is in many ways even nicer than the best dbx unit, probably worth $400 or more on the used market now days, for only $150 or $200 and some soldering. There are a couple of basic design flaws in 3630s that are easily fixed with a capacitor and some soldering. Buy one, fix it up, and use it. you'll be impressed. it's a great compressor with a few major messups in the earlier production units. The later units are much better, all of them are easily fixed.
Cheers,
Don