Search online as well. You can even order through places like Walmart.
Of course, having a local dealer who can fix problems for you and help your mom is good. Unfortunately, you may pay heavily for that service.
Medical billing is also a nightmare. You are often quoted one price and charged another. Then insurance gets blamed. Then they have people who are skilled at harassing weak, old people into getting them to pay the added price.
BTW, the online stuff isn't necessarily good, and the "full service" dealer stuff isn't necessarily bad. You have to do your research and take your chances.
For instance, look at the "list" vs. discounted price
here: $8800 vs. $2695. That gives you an idea how much prices may vary depending on how you buy it.
Unfortunately, I don't have direct experience with what brands and models are good and bad, but there's a lot of info online. There are also lots of low class outfits who know how to post bogus info online on their shoddy products as well.
You may also be able to rent one for a short period of time until you figure things out, get her adjusted, etc.