I'm a total noob on this forum, and heck, I'd totally have taken you up on it given our agreement was solid and I wasn't already making a bot for myself (conflict of interest). But at least I can give you some pointers from the perspective of a programmer who knows something about trading.
What do I mean by a solid agreement? Firstly: mutual trust. Not only is it the programmer who can run off with your code, but you could also run off without finishing payment. So without some sort of way to know you can trust the other party, both sides should not commit. It's best to see if you can find someone you already trust.
Some people here already said. IF the programmer is any good (ie: knowing about trading and being a smart/adaptable programmer with a lot of domain knowledge), he/she will be expensive. If the programmer is not expensive, then you start to run into incentive problems. So, yes, the idea of getting the job done for less than $200 on freelancer from a stranger is a horrendous idea, especially if you value your intellectual property (your idea) as a trade secret. The best way to get someone to not run out on an agreement with you is to give proper incentive. $200 is not an incentive to make a program which a buyer will turn around and make millions with... It is more like an incentive to turn around and try to make some money off the bot itself. Yes, programmers experience FOMO too.
So how do you create incentive and how do you further protect yourself? Well, I don't know about where you are, but in the US there are protections for freelancers. If you're a programmer a software product was made in your own home, and not in the office of a company you are on salary with, this product is technically yours. You have no legal obligation to keep it exclusive to your client. In fact, if there is no NDA and there is no Non-Compete agreement, then you have no legal recourse for stopping them from taking the software they made and doing what they want with it. Think about incentive again. Personally projects like this, if they are sufficiently complicated and I will not be able to sell it later or am bound by a contract, means one thing: I want to get paid well for my work. In the contract, you sould include the terms for buying the rights and full license to the software your progammer makes, and it should be a decent price. An example would be... If this thing takes me a month or two to complete and I will be giving away my rights over it, I'm probably going to want at least $10k.
That being said, what does $10k get you? Well, firstly it gets you piece of mind because a large chunk of that sum, or quite possibly all of it would be paid when I turn the software rights over to you. This means I am now vested in completing the project properly. What is to stop me from taking the money and selling a version of the bot anyway? My honor. Besides that, legal recourse (which will cost you a lot, but you should be ready for that contingency.) Think of this the same way you do trading. Set your limits, set your risk, set your stop loss. In this case though, it's all about the contract, which should be legally witnessed by a notary public when both of you sign it and probably drawn up by a lawyer.
If on the other hand, your bot is something simple but unique, well, less of a price, etc. but still trust is that key, and then incentive for the programmer to follow the rules and stay on schedule.
