If you're okay with older homelab-esque equipment, the ERA, also on eBay as Calgary Computer Wholesale, often has really cheap rack mount stuff. This being said, the ERA is a pretty sketchy organization overall (it's closer to a small e-waste recycling business that takes advantage of its status to reduce liable taxes (with variable employee salaries equivalent to dividends) and take advantage of free volunteer labour, than an actual non-profit organization). Sometimes, provincial government surplus auction sites have rack mount equipment as well.