This is part of an series of budget decks, you can find more here: https://www.reddit.com/r/EternalCardGame/comments/e5fvgi/ten_budget_expedition_decks/?
Yeti's like to attack and throw snowballs and other spells. So, we hit them with our units while killing theirs with our spells, until that fails and we kill the opponent with our spells instead, hopefully buffed by our Wizened Crone and Iceberg Warchief who can make even the smallest snowball hurt quite a bit.
Theme deck upgrade:
Market: - Mortar + Prodigious Sorcery