Does you son want you to move with him? Maybe he just wants to move with his partner? Y’all going to live together?

America is a lot more expensive than the UK. If you have no savings / on a minimum wage job you’d struggle

You sound like you have no special qualifications/skills to qualify for a visa

The reality is, you are not moving to the USA anytime soon.

Mint comes with issues, they are cheap for reason, however I’m pretty sure I used them before T mobile took them over so they may have improved I could not use my mint number when travelling in Europe last year however my AT&T number worked fine