Yah - I didn't sell any items either, in fact I bought every single one since I needed them for Crystals just like you.
I did do every item upgrade fight, so that probably got me quite a bit of extra gold here and there. I also was raking it in when I was in Helvedia.
You know, I think before I finally got more Dragon Riders, I had single stacks of them summoning like 7 or 8 dragons a pop. It was ridiculous.
My ArchDemons would distract with their Volcanoes and the Dragon Riders would summon 3 random dragon stacks. Then the fun would ensue.
/C\/C\