This mod adds 14 custom blocks that vaguely resemble a shop counter. Each of them have an item from Minecraft on the side facing the "customer".

There is also 5 coins added: Copper, Iron, Gold, Diamond, and Emerald.

I recommend JEI or REI for the Base Shop Block, Bank, and Copper Coin recipe.
All other coins are used by combining 4 of the previous coins in the new Bank block.

While all of the coins can be crafted in roundabout way, they can also be dropped from various mobs. The harder the mob, the higher quality coins you'll receive. The drop rates are listed below:

Zombies, Creepers, Skeletons, and Spiders:
50%: 1-4 Copper Coins

Blazes, Ghasts, Wither Skeletons, Hoglins, Zoglins:
50%: 1-4 Iron Coins
(Magma have a 10% chance to drop 1 iron coin)

Shulkers and Enderman:
75%: 1-4 Gold Coins

Guardian, Vindicators, and Evokers:
25%: 1-4 Diamond Coins

Elder Guardian and Wither:
100%: Either 4 or 6 Emerald Coins

End Dragon:
100%: 16 Emerald Coins

While not entirely useful by itself, unless you enjoy the aesthetic, this mod was made with the intention of combining it with 2 other mods for modpacks, both by SpaceCat_97:

Custom Villager Professions: https://www.curseforge.com/minecraft/mc-mods/custom-professions
Custom Villager Trades: https://www.curseforge.com/minecraft/mc-mods/custom-villager-trades
Use the new shop blocks as the POIs for your new professions, and add whichever trades you want to your new villagers.

Images:

Please let me know what sort of features you'd like from this mod, and I'll consider implementing them.

Shop Blocks & Coins