Went to homedepot to buy wire for hottub/spa
Aprox 80ft in the four colors, red,green white and black
The guy helping me told I could save a lot of money buying a roll of black and mark the ends red,green,white and that it would pass inspection
Has anyone heard of this Im in Michigan
Thanks in advance

It would be a violating of NEC pool and spa codes to use anything but a green wire for the ground (no, you can't mark a black wire green)... not to say you're local inspector would necessarily know this, and not pass it.