We got a treadmill for the wife as she was too emabarressed initially to go outside. We knew we'd only need it for 6 months or so by which time she'd either have given up or gone outside.
Knowing this we weren't fussed about a good warranty, a name etc and spent £250 on a chinese import off ebay with a 22hp motor, powered incline, speed from 1 - 20kmph. Looked terrible, plasticky etc but did what we wanted. 13 months later it went terminally wrong and would have been cheaper to buy a new one than to fix but it had done all we wanted by then and Mrs C was running outside.
Could be a similar situation with your wife & daughters in that you only want it for a short time and whatt cost you're willing to pay for that short time?
Having said that, I'm with jj & cougie. When Mrs C was using it she was the only one. I was outside.........