Every Apple Watch owner should have two charging cables. One for their nightstand, and one for their luggage. It’s a very easy cable to forget at home, and if you find yourself on the road without a charger, it’s painful to march into an Apple Store and fork over $29 for a new one.
There haven’t been too many third party options to date, but this model is MFI certified, and only $20 today with promo code RV66EE4N. Just note that it won’t fit in most Apple Watch charging dock accessories, so you’re probably better off putting this one in your bag.