Gina can volunteer if she has a problem, or purchase the slave.
3 gold is a lot of money. Getting your worth out of it is required. Slave is already ill-mannered expressing anger regarding the consequences of the master's profession and should have been disciplined. The better behavior by the slave is re-evaluating their resilience and reliability which caused their master to lie to them. In other words, regretting their weakness. Not entitling themselves to another's business. MC could've just said none of their business, of course.
Everyone wants a drunkard to just sink funds in this girl with no pay off, become a noodle spine; exact opposite of the character he is.
Housekeeping with the debt of feeding her, means service measured in years not months to break even (not profit), especially with the cultural stigma affecting how others have seen him.
Y'all want to free a stranger slave for no return ($0 back) with 2 months salary (shelter and food) gone?
Bottom line men choose pussies over hands all the time (prostitutes). Anything providing that with cost efficiency, even from poor resale value back to the slave shop, will be used.
He gave the 'meat' a chance to profit him. This is the logic of property which has maintenance costs.
Also, there is no guarantee this MC won't die tomorrow with their line of work.
Of course, morally, fornication is bad.