MacBook Pro Charger & Cable
You can get by with the one charger that comes with your notebook, but it's a smart idea to pick up a spare MacBook Pro charger to have on hand if you aren't using a dock at home or the office.
While USB C is a standard, you can't use just any cable and adapter to charge the MacBook Pro with USB C. This is especially true for the 15-inch MacBook Pro that requires more power.
Don't mess around with charging your MacBook Pro. At this stage it's smart to go with the official MacBook Pro USB C chargers.
We may see third-party affordable options arrive, but for now you should go with these options. If you need a longer extension you can pick up the extension anywhere that one is sold. Amazon offers one for $8.75 that will let you extend your charging capabilities. You can also use one you already own.