This is a two year old thread but I will have a crack at it anyway.
No, you should definitely not buy a very low end bike that is not in good running order unless you have some sentimental attachment to the model.
The cost of the small odds and ends you will need to get it working will add up very quickly. The parts for older bikes are also highly interchangeable and you can usually find ones that fit, but they probably won't match and will stick out like a sore thumb. Things like shifters, derailleurs, seatposts, etc.
You can get working bikes in good shape for probably less than you will spend on that thing because it probably needs more than a chain and you can't verify if everything is working.
My favorite checks for a bike are to make sure the pedals, crank, fork, and wheels are only free to turn, and do not clunk around as if the axles were loose. They are not hard to adjust but if the bike has been used with them loose, the cones are probably shot.
The rims can wobble a little when the wheels turn but they should not be able to wobble from side to side when the wheel's not turning, not even a little bit. The same rule should go for the cranks, fork, and pedals but the pedals are easy to replace....but like I mentioned, that's going to be another $15-20 for cheap ones.
You should also do an online fit calculator and ensure the bike is the right size for you.