Like most Magic: The Gathering cards, the value of Artifact Ward depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Antiquities)
Or, you know, just return it to your hand so you can cast it again and make another token
Lorwyns (2007) Card not found is a bit on the expensive side for this effect, but it also clashes, which means you might be able to use it again
Location cards have the same features as standard cards, including a Willpower stat, which is used when opposing players challenge the card to banish it from play, but instead of a Strength stat, Location cards have a move cost
How much is the element of surprise worth when it comes to other players expending resources, as opposed to you just playing it down as normal and being immune to whatever's coming anyhow