How can I modify my meta_query to work with prices that are stored in the database that contain dollar signs and commas?

Would it be better to ditch the JS formatter on the input fields in the admin and instead add the dollar sign and comma separation on the front end?

Yes, definitely.

This seems more logical, but then it raises another question of how to
prevent a user entering a dollar sign or comma formatting in the
admin.

Sanitize the input before storing it, using absint().

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)