Once during your turn (before your attack), when you attach a Water Energy card from your hand to Swampert, remove 1 damage counter from Swampert.
Attacks
Water Arrow
Choose 1 of your opponent's Pokémon. This attack does 20 damage to that Pokémon. (Don't apply Weakness and Resistance for Benched Pokémon.)
50Waterfall
How much is Swampert #23/109 worth?
Swampert #23/109 is a Rare card from Ruby & Sapphire (2003) — today it trades at roughly $5.33 ungraded.
Grading changes the math on this one: a PSA 10 is valued around $549.99, roughly 103.2x the raw price, while a PSA 9 sits near $59.99. 164 copies have been graded to date, and 16% of them came back a 10 — worth knowing before you pay grading fees.
These figures come from nightly market-data syncs verified against completed sales. Use the chart above to see the trend before you buy or sell.