Crafting & Shop

General: 

In this game anyone can make magic items provided they meet the requirements of being proficient with Arcana, proficiency with the respected tool, the appropriate level, having a recipe of that item and a week to dedicate to crafting that item. There are arguments of some tools that require the use of two tools but for simplicity we are going to make those to lean towards one or the other or if it's in the middle, then it comes up as either or.

Recipes: 

Now adding a bit of complexity lets ask the question of how your character knows how to make that one or those magic items. We simplify this with your character experimenting about the formulas of the magic within that week of warp travel and applying the effect within a secure protocol, that includes the aid of Senior officers aiding you. After completing the warp travel, you have successfully crafted your recipe. Once this recipe (of what ever item your character went for) is complete you can now make copies of that item to give to your friends, your self or sell on the market. If you are creating consumables then the character makes two instead of one.

Rarities: 

For this we are using the rarity as a complexity. The higher the rarity the more the magic formula shows range of difficulty. As you level up, you gain understanding, the items become unlocked for you to make recipes and ability to craft them. 

Level 1-4 = Common/Uncommon
Level 5-10 = Rare
Level 11-16 = Very Rare

Shops: 

Purchasing: 

With this setting magic items are abundant to players so to simplify and counter balance assume all magic item for purchasing are at max value unless they are consumables then treat those at half value as "Xanathar's Guide to Everything" suggests. If players are looking to make deals they can play the haggle game with the Referee to get a discount. The prices becomes referee dependent.

Common = 10 Platinum Pieces
Uncommon = 50 Platinum Pieces
Rare = 500 Platinum Pieces
Very Rare = 5,000 Platinum Pieces

Selling: 

To provide a simplified challenge to the players, they do have to compete with other venders so player's character should sell their crafted items at half value or play the haggle game with the Referee to convince a customer to purchase the item for a "reliable" price.

Common = 5 Platinum Pieces
Uncommon = 25 Platinum Pieces
Rare = 250 Platinum Pieces
Very Rare = 2,500 Platinum Pieces