There are legit communities which already collect that information in structured ways. For example https://www.ozbargain.com.au/ https://www.ozbargain.com.au/ i

There are legit communities which already collect that information in structured ways. For example https://www.ozbargain.com.au/ https://www.ozbargain.com.au/ is quite Australia-oriented, but could be turned into an extension bringing up the coupon codes automatically.