Discount websites/apps

As a solo caravanner I mainly stick to CC sites, as private sites usually charge for 2 people, which is cheaper per head if you have 2 people, but is more expensive per head if you don't! However, you can occasionally get cost bargains from discount websites or apps - I have recently been able to get 3 nights at Orwell Meadows near Ipswich with a Groupon deal, and Tickles (!) was doing a deal for a Suffolk site called the Hollies. Has anyone come across any other good discount deals?