If you mean the money you use in LittleBigStore, you need to have a credit card. This shop option is only for those that have a Internet connection useable on the PS3 (WLAN works). In the main PS3 menu, go to the PS3-Network logo and there's three options. If you haven't logged in yet, select Log In (Or something similar) and then the Username options or Profile Options (Anything similar to that) It's probably Profile Management. There you should enter your Billing Information and so on. Then, go LittleBigPlanet-->LittleBigStore. Choose anything form there, and then go to the cash desk (Or wherever you finally buy that stuff). There, in the upper right corner you see the 'Add funds' button. I'm not sure what after that, but I guess you just follow the instructions there.