I installed a retractable screen door by myself (I'm not very strong or handy) a few years ago. Cost: about $150 from HD. I didn't get it quite perfectly level, and I allow it to get pretty dirty, so after the first year, I just decided not to use that screen for walking through (there's another entry very close by). It works fine as a window for cross-vent, but if I had to use it every day I'd remove it. BUT...one year a pal came over and spent about an hour pulling up grime and dirt from the bottom track and spraying WD-40 in there and working the screen back and forth and then it worked great...until I rented the place out and it basically sealed itself shut again.
For my new place, I'm buying one of the magnetic magic ones, but instead of attaching with velcro at the top, it works with a tension rod (for a sliding glass door). Not sure yet how that will be, but two neighbors use them and swear by them.
Update: It's great! Better than the sliding screen that comes with the door.