For the first step you need to decide what color(s) and type of duct tape you want to make your money pouch in. Duct Tape comes in many different colors and in varying thicknesses. For something like this I suggest using a lightweight thin duct tape, such as a generic brand or Duck brand tape. It should take only part of a roll or one small roll.
Step 2: Gather your tools
All you'll need is a clean workspace and a pair of scissors. If you can't find a clean workspace though, any place will due as long as you have enough space to work.
Step 3: Create the Back and front
This step is pretty simple just take a piece of duct tape as long as you want, about the size of a dollar, but smaller works well to. The process for the back is repeated to make the front. Don't worry if your duct tape wrinkles, as long as it remains relatively even. If you have any extra duct tape hanging off just wrap it around. After you have both pieces made, line the two pieces up and use a single piece of tape to bind three of the sides leaving one of the long sides open at the top.