I don't know. If you're not hiring them full time, it might be a bargain, and save you a bunch of money. Particularly if you're trying to architect services from the ground up.
Some people are "force multipliers". In that the work they do can save 10x the engineering time. Dennis Ritchie was maybe a 1B force multiplier.
I was paid $100k/year about a decade ago and saved the company I worked for $4M.
In short, you don't know what you don't know. How much is it worth for you to find out?