Before everyone goes nutty on bike components etc. just posting this to give options over more expensive brands.
Not great quality, but if looking for cheap bike for a pre-teen that will probably outgrow it in a few years, this might be a good option. Seems to be on par with the $100 bikes sold at Kmart or Wally World but for almost half the price.
Reviews are mostly positive with negatives mainly about plastic parts or assembly.
I probably wouldn't suggest taking this out on trails, but for your kid to ride in the neighborhood on paved roads, should be ok.
Haven't tried applying any coupons, so if there are some floating out there, this might be even cheaper.
Boys 24 inch
Girls 24 inch
Mens 26 inch