I don't know how it is in Brazil but in Europe and the US offices frequently go out of business that have dozens if not hundreds tiny desktop computers in their

I don't know how it is in Brazil but in Europe and the US offices frequently go out of business that have dozens if not hundreds tiny desktop computers in their bankruptcy auctions. They've got i5 cpu's 4-8gb of ram and 128gb SSD's and go for (much) less than a hundred bucks. Stack 3 of them and you have a kubernetes cluster that you could carry in one hand and I think outperforms the 7 raspberry Pi 3's. Servethehome has a series of articles about the machines, though they're focusing on the slightly higher end ones.