Infiniti Squeak

I’ve got a 1998 Infiniti I30 with 125,000 miles. I need to make it last a few more years, but of late it has been nickeling and diming to death with repairs. The latest symptom is a squeaking/squealing that sounds as though it is coming from the tires. It initiates when I step on the brakes first thing in the morning, but will intermittenly (sp?) stay on without engaging the brakes. Anybody? If you know an estimated cost to have fixed, that would surely help. Thanks in advance