The problem with a lot of regular ESC's is that they have a reverse delay, and when you push the trigger it applys the brakes but doesn't go directly into reverse, which is bad for crawling. The moped ESC's are really cheap and a lot of guys are using them in crawlers. I haven't run one so I can't tell you exactly how they run. Another nice ESC that's cheap is the mamba 25 if you can find one used. Also, if you can run across a nice used sidewinder, they've been going for around $40 used on the forums and it's one of the best esc's on the market for crawling.
Whatever you get, you want to make sure that it will go into reverse as soon as you push the trigger forward, with no delay. Another ESC that's super cheap and I've seen guys use is the Dynamite Tazer. I don't know if it has reverse delay, but it goes for around $15.
What motor are you going to be running with this ESC? A high turn lathe motor?
I know you're on a budget, and you can get some nice ESC's for a decent price, but this is one piece of the crawler that I think it's most important to spend a little money and buy a quality ESC.
The Castle Creations mamba 25 can be picked up used for super cheap, and same with the sidewinders if you find a good deal. If you want, I can help you find a mamba 25 ESC for a good deal, probably not much more than some of those that you linked to.
