One of these, found in the discount bin in a nearby supermarket for about €10-20: https://www.discounto.de/Angebot/BESTRON-Hamburger-Maker-AMHM200-9967861/ http

One of these, found in the discount bin in a nearby supermarket for about €10-20: https://www.discounto.de/Angebot/BESTRON-Hamburger-Maker-AMHM200-9967861/ https://www.discounto.de/Angebot/BESTRON-Hamburger-Maker-AMH... There's probably also a cheaper source for the form and squasher if that's all you need, but it came with them so I didn't look for that separately.