I think a treadmill would be pretty hard, unless you're just walking on it, and I think you'd benefit LOADS more from walking outside. I really recommend trying that.

As for having an exercise machine though, maybe a bike. You can start off slow and just do as much as you can. I think it's just a personal preference but I also just prefer them to treadmills, they don't wear me out as much (but enough) and they just seem much less boring! Of course better to ride a real bike outside though :P (i've been saying for MONTHS I'm going to ride my bike but feel so anxious about being SEEN on it outside that I haven't done it yet)

I think even if you do 10 mins exercise a day (or when you can manage it) it's better than nothing and it's a start, you'll eventually build yourself up to more. And it doesn't have to be about pure exercise, even cleaning the house (oh joy) can be a good workout.

This is really making me think I should exercise too! I feel your pain with the no motivation thing. I've been saying for monthsssss I need to get in shape and get fit.