As Nekotee said, gather all the items yourself and make them yourself.

I made three sets of IL170 crafting gear by gathering all of the mats by myself except for griffin hides and bear fat. Everything else I didn't pay anything for.

Yea, it took a really long time, but I have lots of leftover mats I gathered while gathering the other stuff. I got over 1000 Hardsilver and Aurum Regis Sand when I was gathering other stuff.
So far, I've made 1,800,000 gil just from selling stuff I gathered aside from what I was actually aiming to get. (And I haven't even come close to selling everything yet.)

It took a few weeks of patience, but I still have lots of gathering scrips and crafting scrips leftover too.