How much money do tire shop owners make?

Depends. Some earn an income of $150-200,00 or even more if they are good business people.

Others claim to earn only $30-50,000, but are often participating in tax evasion when they report such a low income. Since they are mainly a cash business, they can participate in many different tax schemes to avoid paying their fair share as a law abiding citizen.

Hopefully the IRS performs more audits on these sort of small business; or hopefully these disobedient businesses start following the laws.