Never EVER buy a cheap chinese cord from eBay/7-11 etc if you plan on having a long lasting, functional cord that won't crap out on you at the wrong moment. These cords have a habit of breaking within a few days to a couple weeks. Why? Because quality cords have a special chip that regulates the voltage such that the cord doesn't burn out. The cords MUST be MFi certified by Apple in order to ensure regulate the voltage properly. This costs money. Non-MFi cables might be cheap, but once you burn through 10 cables in a month you'll understand why you should get a legit certified cable to save money in the long run.
If you need an iPhone cable, ALWAYS buy a cable that is MFi certified. These cables will last pretty much forever if you keep them in good shape. My favourite place to get them is Primecables.com. Fair priced and good quality. The other good alternative is the AmazonBasics brand.
You can get a list of MFi certified cables here:
https://mfi.apple.com/MFiWeb/getAPS
That said, if you need something quick and don't care if it breaks within a few days, I would recommend Dollarama. They are around 2-4 dollars depending on the length.
Edited by ron546, 2017-11-09 11:37:24