I just got home from Michaels and the 12" square plastic storage boxes are on sale for 1/2 price. Here they cost me $14.98 Canadian and they were on sale for $7.99! So I would imagine that in the US they would also be 1/2 price and less than $7.99. I'm going back next week to get 4 more!
They are great for storing the fabric and pattern for a project or the completed blocks for a quilt.
Here's a link to a previous post about these boxes - it has pictures so you can see which ones I'm talking about.