Don't know how to properly ride a bicycle? See link below...Bicycling Street Smarts. Note it says "Street Smarts" not Sidewalk Smarts. Riding on the sidewalk is technically illegal in most areas.
Up your price range at least $100see a REAL bicycle shop if you want a quality product. If you want a piece of junk - see Wally World. Discount store bicycles - if ridden on a regular basis - break downfall apart quickly - like in a year or less. They end up costing more in the long run for repairsupgrades than a quality bike from Raleigh, Specialized, Trek, Giant, Cannondale or other fine names. Got an R.E.I. store around? They also sell quality bikes.