Snow Biker is one of the three skins released under the Wild Santa part of the Santa offer. It could be purchased as part of an item deal in late December 2017.
Snow Biker could be purchased for $9.99 in a deal that included 16000 coins. It was not available for individual purchase and may not be available for purchase in the future.
Details of this offer may vary depending location, platform or time.
Note: The Wild Santa sub-offer was released again for a limited time in mid December 2020. The item deal for Snow Biker was updated to the following: $4.99 for Snow Biker and 6700 coins