You can't have too many charger these days, particularly since so many Samsung phones don't come with a charger in the box now. A 25W charger is your best bet as most of the company's recent devices support at least this level of fast charging.
The official 25W Samsung charger is available for 43% off today. This also happens to be the version with the cable. Samsung sells one without the cable but with this significant discount, getting the full package is more feasible.
Normally priced at $34.99, you can buy the official Samsung 25W charger from Amazon for just $19.99 today.