It is hard to say, but I doubt you would get it done for $200.
If you were to do yourself:
-100' of 10-2 wire ~$120 retail around here (50' might work depending on the run)
- basic tools
- 30A breaker
- might need junction box and flex conduit (depending on what inspector wants to see)
- permit probably needs to be pulled
- sales tax
Although an electrician can buy this stuff cheaper than you can, the reality is that these materials probably add up to more than you think. You also have to figure that he might have to spend a couple hours crawling around and some spots might be tough to access. It also depends if he has a clear shot from the panel to the crawl space (unfinished area). If the panel area is finished, it will take more time (and $$$) as he has to fish the wire through the wall.
You have to figure that it might cost $200-$300 to do yourself between the materials, tools, and permit. Then you have to consider the labor and travel time (trip charge) (the contractor has a lot of overhead between insurance, salaries, tools, training, etc.).
Your best bet is to contact a few other guys and pick one that is somewhere in the middle.