What I did in the end was going to Staples and buy some "mailer boxes" in different sizes so that I can store the items. Since then I have found them for a significantly lower price online. I'm including the link but realize its a Canadian Supplier. I'm sure there is something similar in the states. I'm also putting a couple of pictures of how I use these types of boxes in this post.
Hope this is useful to someone :).
The place I have found to order these boxes is called Uline. This is a link to the page that has the box sizes and the prices.
Examples of how I use the boxes:
Here are some boxes that I used to make "Alphabet Boxes".
Here is an example of a box that I use to store an activity with hands on items.
Here is an example of a box used to store a card activity. Inside the box are a bunch of different sets of cards related to the concept on the outisde of the box. I put the sets in envelopes (or half envelopes) with answers or content writen on the outside.