All level 45-50 gear (non star), are very easy to HQ, and sell quickly at a decent price. This is due to people buying them for spirit bonding.

I make a lot of gil just off basic mats, like cloths/leathers/ingots, etc. For example, yesterday I quick synthed three stacks of boar leathers while I watched some TV. All said and done, I'd made 150k profit for time spent watching House of Lies. This isn't the most glamorous way to make money, but it adds up very fast.