As speculated by TCGplayer, there could be several factors contributing to the card's massive price point, most obviously the fact that's from the recent Twilight Masquerade set which is still relatively new
Swanna Stage 1 HP 90 Swanna is a Stage 1 water card from Pokmon TCG Pocket
When going second, the most important of these three cards is Just Shut Up and Come with Us
In the case of the Salamangreat deck, these abilities include being able to recycle themselves as tribute cards to eventually allow one of the most powerful cards currently in the game to run roughshod over your opponent
If you are looking for a budget alternative, then this can work
Cards like Fierce Guardianship, Lightning Greaves, Tamiyo's Safekeeping, Slip Out the Back, and Malakir Rebirth keep your commander safe so that your opponent doesnt just remove it