According to the tooltip above, these normally go for a little more than 4 million ISK each and I got a 5 stack for 4 million each. Since I've never seen anyone selling them in the region I decided to put them up for 45 million each (more than 10x what I paid for them) and see what happened.
A bit less than a week later one sold, paying for the entire 5 stack more than twice over.
Someone else was buying them too at first, a cut war with him is why I paid so much for them in the first place. That competition is gone now though, for the time being I have the entire regional market on both buy and sell orders to myself with no competition.
Maybe I'll sell a few more before new competition sprouts up and maybe not. Regardless, I've already bought 15 for 60 million and recouped 45 million on a single sale, leaving only 15 million more needed to cover the cost of them all and I still have 14 left to sell. It's unlikely I'll manage to sell very many at that kind of profit but I can probably get more than 5 million each (maybe a lot more) and I'll still wind up with a pretty decent profit on the lot in the end.