Depends on how you define affordable. You can buy a $150 push mower at Walmart, Sears or Home Depot which will be ok and if you take good care of it it will last several years. I spent over $300 on a Toro personal pace self propelled with bagger at Home Depot and it has been great. I've had it for around 10 years and the darn thing just works every time. Never gives me trouble starting, even after sitting all winter and I admit I could have taken better care of it. It always runs well, cuts well, bags well when I choose to bag. I usually run the side discharge shute or mulch. Anyway, it's probably at least $350 now which may sound like a lot for a 22" walk behind mower but it has really been worth it.
My wife loves it too. She likes to use it for a little extra excerise and the personal pace feature works well. The more you push on the handle the faster it goes so if you walk fast it just naturally goes faster, if you walk slow it naturally goes slower.
Good luck on your search!
