Probably many people also figured this out, you have to have the ING 5% pay wave rebate card, you can use it together with the tell coles $5 off voucher.
Just purchase between $100 - $105, with the tell coles voucher you bring the total cost down to below $100, then you can use the ING pay wave card, total savings is almost $10
If your ING 5% rebate is about to expire, just go and buy a bunch of coles gift cards
the point is to buy say $104.99, then you can use the tell coles voucher to bring the price to 99.99 (save $5), then you can use the paywave to save another $5