I'm still using several wooden wine(? They could have held other bottles too; they're a bit small for full scale wine bottles...) boxes I got as gifts many, many years ago. They're square(ish) and hold about 64 vallejo type bottles each, comfortably.
They were free, they're sturdy, and hold enough bottles for my needs. Disadvantages are that they are basically open squares, with no grid or frame to hold bottles in place, so jostling a box when it's not completely full will result in bottles toppling and getting out of place (red bottles inbetween green ones, ugh), and they have no carrying handle to tote them around. So when painting away from my desk, I have to stack them and carry them like that.
But considering they were free, and 99.9% of the time sit in a drawer beneath my desk, I can live with it. Eventually though, I'm hoping to replace them with some sort of purposebuilt paint storage rack of sorts...