hi jim
that's a reasonable approach,
with these caveats...
a good seat is critical to enjoying a bike ride, usually these bikes don't have great saddles so riding hurts...
good brakes are very important, usually these bikes has IFFY brakes (and hand levers), which again doesn't encourage riding.
simple/reliable shifting makes riding more fun. there is nothing more annoying that having the chain pop off going up hill...
or having the gears 'jam' in some way, or need to 'adjust brakes and cables for every ride.
lots of bikes don't get ridden because they have FLAT tires or need a few quick pumps of air...
i'm not suggesting you don't buy and try, and the monetary risk is small...
but another approach is to find a good USED bike, which is moderately priced but better built and equipped.
hey ANY bike that is used is better than the finest bike collecting dust!
oh and GET A REALLY WELL FITTING HELMET!
you cannot upgrade your noggin later...
cheers
2air'