Just two cracks in the neck and the G string tuning knob broke off. How much do you guys think Sam Ash will charge to glue it and replace the tuning knob?

btw, yes I know the G string is strung incorrectly lol. it's not my guitar :P
I'm thinking more than it's worth, sorry.....

But hey, wait for second and third opinions.

In this case, I'd take the strings off, find a hypodermic needle, load it with Titebond, spread open the crack, shoot it full of glue, clamp it up and hope for the best.

for the job to be right, you'd have to putty in the chips along the crack line, sand it out, and refinish the neck. Methinks that would be time and cost prohibitive.
I have made repairs similar to this using epoxy two pack. But I'm with Cranky, better to have fun finding a new one. You didn't say how it happened. Cheers