If you need help implementing your trading system Upwork.com is a good place to start looking for freelancers. You can hire developers for fixed price (for example $200-$300 for simple algorithms) or pay hourly rate if you need continuous support for your system. There are multiple benefits of going through sites such as Upwork instead of working directly with contractors. First, there are multiple developers bidding for your project and you pick the best ones based on experience or completion rates. Second, you only pay after you receive working product while the site acts as an escrow between you and freelancer. All you need is an idea for profitable trading system.