Not to forget: A lot has improved over the years with low-end bikes. Steel rims have given way to double-walled alloy, cotter pins and steel cranks have thankfully vanished, LED lights (and double cables) now seem standard on dynamo-equipped bikes, the cheapest frames are sturdy aluminium, bendy steel sidepull brakes have been superseded by tough efficient v-brakes, 4-point fastening for carriers is now standard, cheap hub gears change silkily instead of the old thunk-thunk-thunk.
As long as there are no gimmicks on a bike like suspension, disc brakes or whatever, there are good deals to be had among the el-cheapos.