$100 to develop an emulator would be a lot like $25,000 to build a skyscraper. Both are ridiculously not even close to covering the effort involved, probably not enough to cover 1% of the project
It's not that it can't be done (well, I assume it can). It's really that as a commercial venture, even $1000 would be a token, and an insulting amount to offer given the difficulty, time, effort involved
I would think even $10,000 would be on the low side, but you might get some interest if you were offering $10,000, probably from people who also don't have a strong grasp of what all is involved to do the job well.
Most people who develop emulators do it for fun and for personal reasons, and usually over a great length of time (months or years). Dozens and dozens of hours total though. You're dangerously close to the famous "that's a dollar an hour" quote from Napoleon Dynamite, and any programmer good enough to code a working emulator that runs on a classic console could probably land a job as a programmer making at least $30 an hour (probably more)