With this story, no one comes out a winner. And it's all because both sides have a misunderstanding. This is a good example of why you should draw up a written contract before any deal is agreed upon - whether you're buying a horse, or hiring a contractor.
It doesn't have to be fancy. Just make sure it details the:
- Work to be done (who's going to get the building permit if necessary), price, when payments will be made, and when the job will be finished.
- Be as specific as possible describing what you'll be buying or the services provided
- Never sign a blank/partially blank contract.
- Keep a copy for your records.
- Make sure it includes both sides contact information and address.
There are also companies online that sell attorney drafted "form-letter" contracts for less than 20 bucks (like http://www.findlegalforms.com/). In most cases, I don't think it's necessary, but if you feel more comfortable using one, it may be worth it. And if it's a big enough purchase, you may want to consider having an attorney look over the contract or draft one up (it may be cheaper in the long run).