[eloff]

If it's possible for your project, use a non-code / low-code solution and build it yourself as much as possible. When you encounter features you cannot do, contract them out to developers on a per-feature basis.

This should let you keep costs under control, while also allowing a non-programmer to figure out which features require programming and which don't, but more importantly - break them up into the smallest features you can which decreases the risk and cost of developing it.

Try a few contractors by posting the features independently, and once you find a really good contractor, use him/her for everything else directly and without a middle-man.