I am interested to buy Nexus 4 16 GB Certified Pre-Owned for $150. Since it is no longer available online and only available instore, I would have to go the the store. The store require me to purchase the sim and would cost me $20. Could I just buy the phone without the sim (e.g. I have one laying around or my friend had a spare one)? If I have the get the sim, why buying the phone online give out sim card for free but not when buying from store?