My bank charges a significant fee for deposits of US Social Security checks. Is this generally a paid service or I should explore other banks and get lower fees?
Banks may choose to charge whatever they want for whatever services they offer (at least, within legal limits), because they are a business. It's unusual for a bank to charge a service fee for cashing a check, but not impossible. As a commenter said, you should consider shopping around for a new bank. Most banks will give you literature regarding their fees upfront if you ask.