Cheapest priced copy (Commander 2021): $0.49 at Card Kingdom, near mint, their price list as of .
Healing Technique 
Sorcery · Rare · Commander 2021 · #390
Demonstrate (When you cast this spell, you may copy it. If you do, choose an opponent to also copy it. Players may choose new targets for their copies.)
Return target card from your graveyard to your hand. You gain life equal to that card's mana value. Exile Healing Technique.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
3 printings · $0.49 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2021 | 63 | Rare | $0.49 | — |
| Commander 2021 | 390 | Rare | $0.99 | — |
| The List | C21-63 | Rare | $0.49 | — |
5 rulings from Wizards of the Coast
- 16 April 2021You choose whether to make a copy as the demonstrate ability resolves. This happens before the original spell resolves. Your copy goes on the stack above the original spell.
- 16 April 2021This means that if you cast a spell with demonstrate and both you and an opponent copy it, the opponent’s copy will resolve first, then your copy will resolve, and finally the original spell will resolve.
- 16 April 2021If you cast the spell and choose not to copy it, no opponent will get to copy it either.
- 16 April 2021If you copy a spell with demonstrate, you then immediately choose an opponent. If they copy the spell, it goes on top of the stack.
- 16 April 2021If the spell requires targets, you choose the target of the original spell as you cast it. If you create a copy of the spell, you may choose new targets for the copy as you create that copy. Similarly, the opponent you chose to create a copy may choose new targets for that copy as it’s created. In other words, your opponent will know the targets of your original spell and your copy when choosing the new targets, if any, for their copy.