Looking for some EX cubes so I can iron out my mags leveling, will pay pretty good prices for a few.

EX-Cubes are not tradable, you can't buy them on personal shop. That's why AndrlCh mentioned about 10-11 star rarity weapons in the other thread. You can buy these weapon and exchange them to EX-Cube on Swap Shop. Still it won't be easy to get a lot of them...