Bought a big packet from the Stationery shop and keep in the freezer so they don't perish. In NZ the 'proper' flying rubber bands would be nearly impossible to obtain and if you could they would be very expensive. I use 12 bands on the wing every flight. 8 crossed over the wing side to side front to back and 4 on the same side, front to back. I also reuse bands a few times until they become soft (quite easy to feel the difference between a good wing band and one that should not be reused) and then into the bin. I also figure that 12 bands gives plenty of surplus holding capacity (redundancy) and if a band should break while flying there are still plenty left to hold the wing. This has never happened to me. I never stretch bands straight from the freezer, giving them the time from home to the flying field to warm to normal temperature. As a check from time to time (like 2 or 3 times a year) check the rubber bands are holding the wing secure. I wipe clean the bands after flying with a rag and then I store the rubber bands in use at the time, in a sealed plastic container with some talcum powder in it to absorb any fuel residue. Never had an issue with the wing moving in flight. The plane does loops and other basic aerobatics.