You really don't want to buy a bike from walmart. They probably have other fully assembled bikes, but they will likely be put together by the same person who didn't know what they were doing on the display model. The reason you don't buy bikes from walmart are they are the lowest of the low end. You can get a low end bike from a bike shop for just a little more money and it will be significantly better, not to mention weigh half as much. The guy who said he bought 2 bikes in the last 3 years and they last should give you a hint. I buy quality bikes from bike shops every 6-8 years and sell the used one in excellent condition to someone else to enjoy. I take my bike off road every week and it takes a lot of abuse. I've had a walmart bike. They do not compare. If you plan on riding it a lot, buy from a bike shop. You will thank yourself down the road.
Any bike shop will have models in the $200 range. These bike are superior to everything WalMart carries. I hope I helped a little.