Maybe start a system where people could lend their devices to the space, so they could earn some money on them long term. Depending of the initial cost of a device, I'd pay 10EUR-20EUR every time I'd use a special device. 10% of the profit goes to the makerspace, 90% to the device-lender. With 50-100 uses, you'd start making money. I could see something like this work.