Cheapest priced copy (Amonkhet): $0.35 at Card Kingdom, near mint, their price list as of .
Spidery Grasp 
Instant · Common · Innistrad · #204
Untap target creature. It gets +2/+4 and gains reach until end of turn. (It can block creatures with flying.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
3 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Amonkhet | 188 | Common | $0.35 | $0.49 |
| Game Night 2019 | 51 | Common | $0.35 | — |
| Innistrad | 204 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 22 September 2011Spidery Grasp can target a creature that’s already untapped. It will still get +2/+4 and gain reach.