Gems Shop

This is a shop in level A. They sell gems:
 * 1 Blue Gem - $2 (sellable for $1)
 * 1 Green Gem - $4 (sellable for $3)
 * 1 Silver Gem - $8 (sellable for $7)
 * 3 Black Gem - $20 (sellable for $19)

Coins will go away if you die/reset. However you can convert coins to gems here at a slight monetary loss. If you stash your gems in the Save Room, they will persist.