At level 50 you can start gaching, which will be one of your main sources of income in Royals. At your level basically what Muren said, you can try to grind at places with decent drops, but again at your level you don't have much option. Just sell resets or rocks until 50 then start gaching.
You shouldn't even worry about money at your level. Get to a higher level and gach to fund your equips up to 4th job, then you can start working on building up your capital.
Head to Stone Masks for a chance at some high priced scrolls Do the Old Raggedy Cape quest if you haven't already. Easy 15m Head to Cloud Foxes for a chance at 30% 2h Sword scrolls. Head to Crows for a chance at 30% Shoe Jump scrolls
Oh and in your 4Xs you can grind at Skele Soldiers, which drop GFA and CFA 60s that I'm sure you could put to great use.