Cheapest priced copy (Commander Anthology): $0.49 at Card Kingdom, near mint, their price list as of .
Assault Suit 
Artifact — Equipment · Uncommon · Commander 2014 · #53
Equipped creature gets +2/+2, has haste, can't attack you or planeswalkers you control, and can't be sacrificed.
At the beginning of each opponent's upkeep, you may have that player gain control of equipped creature until end of turn. If you do, untap it.
Equip {3}
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
6 printings · $0.49 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Warhammer 40,000 Commander | 230 | Uncommon | $0.99 | — |
| Warhammer 40,000 Commander | 230★ | Uncommon | — | — |
| Commander 2014 | 53 | Uncommon | $0.79 | — |
| Commander 2016 | 242 | Uncommon | $0.99 | — |
| Commander Anthology | 208 | Uncommon | $0.49 | — |
| Commander Masters | 369 | Uncommon | $0.49 | $0.99 |
2 rulings from Wizards of the Coast
- 7 November 2014If an effect instructs you to sacrifice a creature, and you control any creatures other than the creature equipped with Assault Suit, you must sacrifice one of them. You can't try to sacrifice the equipped creature, fail, and therefore ignore the effect.
- 7 November 2014The equipped creature can't be sacrificed for any reason. If an effect instructs you to sacrifice it, you can't and it remains on the battlefield. You also can't sacrifice it to pay a cost that requires you to sacrifice a creature.