The Gnome Shop uses Gems as currency, which can be obtained in three ways:
- Each enemy, when killed, has a chance to drop a small amount of gems.
- Watch an advertisement for 100 gems.
- Be bought with real money:
- $2.99: 1500 Gems
- $4.99: 2500 Gems
- $9.99: 6000 Gems
- $19.99: 14000 Gems
- $49.99: 40000 Gems
Gems carry over between levels. The player's current amount of gems can be seen near the top right corner of the main screen.
The Gnome Shop sells six kinds of one-use-only items. These items are useable by tapping on the third spell slot, Bag Pack, selecting an item, then tap the location where you want to use it.
Kingdom Rush and Frontiers
- Dynamite (50 Gems): deals 250 damage to enemies in an area of effect.
- Frozotov (50 Gems): freezes enemies in an area of effect, rendering them helpless.
- Chill Wand (250 Gems): freezes all enemies currently in play and prevents new ones from attacking.
- Heartbox (350 Gems): adds 5 lives to the player's current count.
- Gold Bag (850 Gems): gives the player 500 Gold.
- Fat Boy (999 Gems): calls a dwarven bomber to drop a bomb, killing all non-boss enemies currently on the screen. (Deals 4000 true damage on bosses and mini-bosses)
- Teleport Scroll (75 Gems): carries enemies in an area back down the path.
- Horn of Heroism (125 Gems): temporarily makes towers and soldiers in an area invulnerable, and doubles their damage for 10 seconds.
- Gem of Timewarp (250 Gems): teleports all enemies back down and slows them down.
- Rod of Dragon (450 Gems): temporarily attacks nearby enemies from a static path location.
- Hand of Midas (750 Gems): temporarily doubles Gold income.
- Wrath of Elynie (999 Gems): places a holy symbol on the path, killing all non-boss enemies currently on the screen. (Deals 4000 true damage on bosses and mini-bosses)
- Frozotov cannot freeze Vez'nan while he's still in the tower.
- Chill Wand only affects the normal attack wave; it does not stop special spawns:
- Spider Hatchlings and Mutated Hatchlings hatching from eggs.
- Skeletons and Skeleton Knights spawned from Graveyards.
- Magma Elementals spawned from the crater at the Forsaken Valley.
- Demon Spawns and Demon Hounds summoned by Vez'nan.
- Husks and Swamp Things spawned from the Poison Pool.
- Tainted Treants emerging from the ground at the Rotten Forest.
- Saurian Savants summoning Saurian Nightscales, Saurian Broodguards and Saurian Darters.
- Fallen spawned by Sand Wraiths and the God King.
Chill Wand and Frozotov can freeze bosses too.
Enemies can't regenerate health under Chill Wand and Frozotov, even if they regenerate usually.
- When a frozen Worg Rider is killed, the dismounting Orc Champion will be thawed.
- A Fat Boy deals considerable damage to a boss, but will not instantly kill it as it does with regular enemies. It also does not destroy all of the Shreds of Darkness created by Umbra.
- Using a Heartbox on either Heroic Challenges or Iron Challenges will give you a few more lives to play with rather than just the one.
- Likewise, if you use a Heartbox to go over the standard 20 lives, a boss passing the exit will not result in a game over (as bosses take away 20 lives)
- Gold Bags previously cost only 500 gems but were increased to 850 when the Endless Challenge was introduced, as a means to increase the difficulty of the mode by preventing people using multiple bags of gold in a level to get ahead.
Several items can be seen in the background of the Gnome Shop, a reference to famous video games, films and cultural icons. They include:
- A Maneki-neko.
- An NES controller and a copy of Super Mario Bros. on an NES cartridge.
- A Hylian Shield.
- Cloud Strife's sword.
- The blue knight from Castle Crashers 's helmet.