I'm pretty sure Bev has a vibration machine...but obviously it'll be a while before she gets around to telling you her experiences with that. As for the treadmill, I have one that I bought from a friend second-hand. It’s a very good model & I was lucky to get it so cheap. I use it at least 4 times a week...and yes, they are kinder to your joints than pounding the pavement!
I think what you need to consider is what would you gain by having one? If you honestly would be unlikely to go out in public/go to the gym for a while, then I personally think it would be invaluable. You can work out at home as often as you like, all year round irrespective of the weather, while watching TV or listening to music so you don’t get bored. You can go at your own pace so you feel comfortable & build things up slowly. Buy the most expensive one you can afford...look for second-hand models in your local paper or on eBay, or gyms sometimes sell off older equipment when they upgrade models.
All that said, nothing makes up for the interaction of being at a gym, under the guidance of those trained in helping you improve your fitness...but even if you bought a treadmill, then joined a gym a few months down the line, you would still use it, so I don’t think it would be a waste xxx