Two things - it is totally ridiculous that there are limited snowflakes and you have to use them to BOTH:
buy presents in the store
and
upgrade the “free“ cards in this promo. The free cards should upgrade with tokens you earn or tp, not snowflakes. So if you want to upgrade a stocking stuffer all the way, which I believe is also one of the objectives to earn XP, you have to use ALL of the snowflakes you can earn. What a crock.