@Carlos Araujo I'd suggest working with a local Realtor. If you're not going to do any business with him, pay him for the work.
If you're going to list the finished home with him, he should do it at no cost.
There's more than meets the eye to running good comps and if you get it wrong, it can be a disaster, so I think it's worth getting it done right.
@Carlos Araujo I agree with @Charlie MacPherson , get a local realtor who has a good reputation and get them to pull comps for you. Most will do , with the understanding, if you buy the home, you'll be able to have them sell it for you.
Also, to do a quick and dirty comp lookup, find homes with similar SQFT for home and lot, same beds and bath and that have been rehabbed...best to get within 1 mile radius and within the past year.
All the best!