Here's how I made my cups.
Step 1: Materials
Cork Coasters -- 89cents/ea
Place mat -- $3.00
My cups cost a little more than ~$2.00 each.
Dice cups not only should obscure your roll, but should also muffle the sound so you don't sound like you're pan handling for change. Loud dice cups are the last thing you want ;)
Step 2: Remove Handles -- Cut Cork
Step 3: Cut and Glue Placemat
Measure the height of your cup, and cut a suitable strip from your place mat.
Now, glue your strip to the side of your cup.