When I go away on holidays I like to take a small wallet and coin purse with me. This way I can carry just a bit of local currency and a card without my day to day stuff. I've just finished doing a tutorial for such a nifty small wallet and coin purse. You can download it from here. It has a little compartment with a zipper, a single slot and nice secure velcro fastening. In addition it has a metal clip so I can clip it inside my bag or keep it in my pocket and clip it to my belt loop. It is quick and easy to make and uses very little fabric.