As I said- "Some" Of the cheaper bikes will work. But $ for $- you will get a better bike the less complicated it is. Suspension MTB's don't work in this category and a bike at the same price without the "Bling" of suspension and you have a chance of getting a reasonable bike.

My first bike was a used Apollo 12 speed MTB. Brakes were made out of thin gauge plate but they worked (Sometimes) Gear changers were the basic Friction shifter and never gave a problem. Wheels stayed true for about 3 bike rides so I learnt how to straighten them out very early on and the gearing was 52/42 and 6 speed freewheel with 14/26 gears. Tyres were basic Chensin knobblies that were slow on the road and didn't work on loose stuff- but the bike worked

But my LBS will not work on BSO's. The labour charge alone is more than the bike cost in the first place and that is without the parts that have to be changed.