Existing cheap cards can become expensive
Snecko Oil draws seven cards and randomizes the costs of cards in your hand for this turn. The second effect is not restricted to the newly drawn cards. A cheap answer you already held can change cost along with the rest of the hand.
Compare drinking it before or after using an essential low-cost card. If that card already supplies guaranteed defense, gambling its affordability may introduce a risk that extra draw does not justify. Conversely, a hand full of expensive cards may benefit when ordinary energy cannot play enough of them.
The draw portion is still drawing. Fiddle and Battle Trance can prevent the expected access, so do not count seven new cards through a no-draw restriction. The potion is also a current-turn effect, not a permanent cost change for the whole deck.
Do not treat the randomization as guaranteed free cards. Count the resources available after the resulting costs appear, then choose the playable line. If the problem is merely a missing card rather than unaffordable cards, compare Swift Potion or targeted retrieval in the potion timing guide when those alternatives are available.
