WAIT STOP HOLD IT?!?!
Does your mom need it for medical reasons? If so insurance will help pay for the cost of it.
All you need is an order from her Dr stating she needs one for medical reasons. Contact her health insurance's liscenced DME (durable medical equipment) provider. Usually if you have a Medicare Advantage (HMO type of medicare) you rent the bed and it is less than $20/month. It varies depending on the insurance provider.
There are also some companies around that have medical equipment exchanges here in St. Louis, we have one that is strictly for exchange purposes called St Louis Help (stlhelp.org) You basically contact them ask for what you need, they see if they have it, if they do they hold it for you and you go pick it up. NO COST!!! They only ask that when you are done using it you return it to them. Their equipment is all donated. From indiviuals, nursing homes, and hospitals. Visit their site, they have a phone number, and may know of something similar in your area.