Ask HN: PCB Design help

I have a few PCB designs I need to get designed but I am not an EE and my PCB design skills are limited. I have written up all the requirements and can write all the firmware internally. I'd like to find either a freelancer or suggested (proven) reasonably priced service to get some assistance in getting these complete within best practices. I need reliability out of these and frankly, they are not super sexy or likely super new territory (just new application), they just require high reliability. Most are for the marine or industrial environments, to give some context.

Can anyone point me in the correct direction? Maybe even a rough estimate what to expect to pay per sq inch to design so I don't get mislead? This isn't about getting the lowest cost provider, just a fair cost for a quality design that works.