I second what Sasquatch said. It's gonna be slower than just going to a store and buying a bike, but if I were you I'd grab your husband's friend who bikes a lot and start looking at/test riding bikes from Craigslist. If he's been at this a while he and some online research can tell you which bikes are worth checking out further.
You *can* get decent bikes at Walmart or any of the big box stores. After you buy one though, be sure to take it to the co-op or another trusted bike mechanic, pay for an hour of shop time, and get it a thorough going over/tune-up. Sometimes even a potentially good bike has been put together by someone from the shoe department and you want to start out safe.