My associate and I have worked on ROBLOX for a while now, and have scripted a variety of things, from fully functional NPCs, to character powers, like spitting out fireballs and the like. I have met several Robloxians who would pay top dollar (10k R$+, which is equivalent to about $100 USD) for the sake of a simple script (max 200 lines). We truncate this price massively.
Finding out what kind of script you need done (small, medium, large) can be discussed beforehand, so we can agree on a price, and if we end up at the wrong conclusion, then any monetary fixes can be made.
If we're not absolutely sure that we can finish a job for you, then we will let you know up front. If that's OK, and you still want us to proceed with the job, then we will do so. If we fail to finish the job, it will be canceled, and of no risk to you monetarily.
We're really looking forward to working with you guys!