I do think buying from a large gym that is replacing old equipment could be a way to spend less and be earth kind. Do be very careful when you buy to check that the anti skid is in good condition, that the tread is not peeling and so on. It won’t end up saving you money if someone is injured on equipment that is too worn out. Some of the large lot type stores do have things occasionally…. keeping in mind that they will be home rather than club quality and may not stand up to the greater usage.
An option to buying as cheaply as possible is to try to raise the funds to buy something more durable. Depending on the logistics of the center I wonder if there might be some sort of grant money? It can take some doing to find such sources. The real issue is finding whether there are available sources, and whether you would be eligible… and it would take a fair bit of time to try to get it. If you know someone who is experienced on either grant writing or crowd funding you might ask for advice.
Or doing a pasta supper, or healthy recipe contest, or trot off your turkey walk… something like that.
If you do buy online be careful to read very carefully. I noticed this recently when I was blogging about yoga mats…. a mat may look colorful and pretty in the picture but you have to read the fine print. There is a huge difference between 3mm and 1/4 inch for instance.