I want make a an item with some unique effects, but I want it be balanced and useful without being to expensive. I also wanted some input to make sure the item is balanced well enough before I drop the idea to my DM and I want some experience in crafting unique magic items for when I decide to try as a DM. 

Recently my group killed a large eagle in a mountain cave. I took the feathers and dropped the idea of turning them into a winged cloak with the misty step spell that I know as a Sorcerer bound to it. This would free up a spell slot for me as well as let me pass the spell on to a teammate in item form. 

I didn't drop any details about how it would work or would be made since I don't know. When I asked in town the shop keeper said they couldn't do it here but maybe further inland they could. Sounds like my DM is interested, but doesn't know how to handle it yet either. So I want to give a balanced idea. 

I think I have enough feathers to make 3 cloaks. A right, left, and tail cloak. The Tail I plan on giving to our dwarf bard for reasons, but its the wings I am most interested in. 

My idea is that each wing will be infused with the spell slots I have available to cast misty step. When I get to when I can craft it I expect this to be 4. Using the two wings together, I want it set up so that using the bonus action to cast misty step with one wing will let you cast the same spell with the other before the end of your turn. This gives a pro to having both wings making them a valuable item as a set, but allows the wings to be used separately as well should the need arise. 

Charging the spell slots would require sorcery points. Because they are inanimate objects, it wouldn't make sense for them to be able to charge themselves. Because I am the one that would be crafting them, I figured it would make sense for it to have a sorcerer aesthetic tied to the items. 

Aside from the feathers, how much would it make sense to craft these items and what other type of ingredients would I need? I'm expecting one day and all the required spell slots as far as time as well as a decent amount of gold, but aside from that I wouldn't think it would need much more then that. 

It is just a set of cloaks that can't charge itself and casts a spell that deals no combat damage. Its only powerful if used by someone with a wild imagination. 

One day is criminally underestimating time. I don’t have the books in front of me so I don’t know exact details, but it takes days, weeks, months, even years to craft magical items. 
That being said; Misty Step Cape? Sign me up

Damn, didn't realize it would take so long for the crafting process. Which book discusses crafting? 

Also realized 2 things recently. Misty step is lvl 2 spell and Sorcerers can only get 3 level 2 spell slots. If I can craft it to have more then 3 slots (4 preferably) I will definatly be pursuing that option. 

Also,  I realized that it can technically be called the Cloak of the Two Step when used as both parts. 

Rules for crafting magic items appears in the Dungeon's Master's Guide. There are alternative magic item crafting rules presented in Xanathar's Guide to Everything.