If you have ever lost a bicycle to thieves, then you must be familiar to the sinking, gut-wrenching helplessness that comes with such theft. Although every bike lock can be broken through by a determined thief, a quality bike lock will reduce the risk of your bike being targeted by thieves. Even if for some reason your bike is singled out, a good bike lock will slow down the thief and might even frustrate the thief enough to leave it alone. Choosing the best cheap bike lock under $20 /$ 50 is not easy. The sheer number of bike locks on the market can make it hard to make the right choice. To help you make the right choice, we have compiled a list of the ten best cheap bike locks under $20/$50. Furthermore, we have created a buying guide to help you in choosing the right bike lock.