If you type "aluminium credit card case" into a Google box, you will see photos of hard credit card cases that are a bit like a glasses case,
. They click open and the cards are slotted into a sort of concertina with half sticking out.
They are so much easier to use than those piddling plastic ones with cards entirely in the thin plastic bit.
They cost £1.69 including postage!
I tried to post a link but it took me 6 goes to get a box to write in and then the link came out as gobbledygook.
Will try again later.
Hope this is not too garbled to help!