People make donations to Hackerspaces in different forms. Money, equipment, raw materials, labor, professional services, and food are all great ways to take the weight out of your expenses and not have your Hackerspace spending as much money as it would have without the contribution. Donation jars, cool money-taking robots, PayPal or WePay on your website, and Square are all fine ways of taking "walk-in" donations.
Make sure it's really a donation if it's tools or equipment - some people will dump old or broken stuff on you just to get rid of it, and then you need to call a recycling or trash pickup to get your "donation" out of your Hackerspace.
Some Hackerspaces accept large donations from individuals or companies in exchange for agreed-upon terms or product placement. This can be enormously helpful. But if you agree to do this, just make sure that the terms are in line with the values of your Hackerspace and its members, and that it won't impact the reputation of your Hackerspace in a way you don't intend.
Potential pile of donations. - Photo by reway2007