My meter batteries are available 6 for £1 in Poundland but I prefer to buy them from the local watch repairer as I believe them to be of better quality
Most companies send you replacements free of charge if you have registered your meter.
I have an accu-chek mobile and they take aaa batteries , Accu-Chek even sent me some duracell batteries
Is your meter the contour usb or the contour next usb as both these meters use rechargeable batteries, which you charge via your PC's usb port or once you register the meter you can send for a free mains charger.