Since you are a miner I would highly suggest you to become a goldsmith.
I'm a level 40 gsm now and my miner is only level 30, tho I could make it all the way to 40 and I can still farm the mats until lv 50
(peridot ftw)
All the stuff you make as a gsm will sell for high prices likely, especially if you make high quality accesoiry , it's likely that you can sell a single low level ring for about 10.000 gil, just imagine all the high level stuff Dx
So you can save a lot of money and can also buy the highest materia for your gear :3