Heart Box

Edit 11/01/2019: With the release of the 1.10.33.0 update all the skins related achievements have been fixed. If you have already completed the requirements the achievements don't pop up right away, I had to apply a skin for them to unlock.

Currently unobtainable. The developer is aware and will try to fix it with an update.

You can buy skins with in-game currency that you earn with daily bonuses or resolving puzzles.
You can also buy a pack with all the skins with real life money.
To access the shop you need to be in a level and then click the shopping cart in the top-left part of the screen.

YELLOW SKINS

FACE --- 4,600
Zombie --- 400
Frog --- 800
Bear --- 900
FNAF --- 1,000
Ironman --- 1,500

BOX --- 4,000
Rubik's cube --- 400
Stone --- 600
Toast --- 600
FNAF --- 900
Ironman --- 1,500

HAT --- 1,400
Viking --- 200
Miner --- 200
Headband --- 200
Sheriff --- 200
Meat --- 300
Robot --- 300

BOTTOM --- 1,400
Tool belt --- 200
SpongeBob --- 200
Prisoner --- 200
TNT --- 200
Flamingo --- 300
'Merica --- 300

GLASSES --- 1,750
Purple triangles --- 200
Groucho --- 200
Minion with pink eye --- 300
Cyclops --- 300
Sam --- 350
Ca$h --- 400

EFFECTS --- 1,750
Bubble --- 200
Fidget spinner --- 300
Feather --- 150
Shuriken --- 200
Star --- 400
Ca$h --- 500

TOTAL YELLOW SKINS --- 14,900 or 3,09 € (or local equivalent)

TOTAL BLUE SKINS --- 7,940 or 1,59 € (or local equivalent)
TOTAL PINK SKINS --- 10,890 or 1,59 € (or local equivalent)

TOTAL EVERY SKIN (EXCEPT FIOLET) --- 33,730 or 6,27 € (or local equivalent)