How to make a DIY bicycle lock:
a similar lock will cost about 100 dollars from a bike store. The benefit of buying in store is the warranty that generally comes with the lock. If you send in a cut lock, you will be reimbursed with the price of the bike.
This is a cheap alternative to the store bought lock that will look just as beefy and can be done on a budget. All you will need is one or more popped tubes, a padlock, electrical tape, and a length of chain that can be bought from a local hardware store. When selecting a chain size, pick something in the middle. You don’t want something too bulky and heavy or too light and fragile. The length will determined by your body size. Take the chain, wrap it around your body diagonally across your chest to determine the length needed. This is if you will be wearing the chain when you ride.
Take your tube, cut the valve stem off, and cut the tube down the middle and wrap your chain in it. You can do as many layers as you like or have tubes for. The more layers the more comfortable the chain will be. Take your electrical tape and wrap the ends of the tube. Add the lock on the end and you have your DIY lock.