Schlauchboot kaufen

Hi there! Some friends and I would like to go with a Schlauchboot down the Saale tomorrow. Buying one online isn't an option due to the short notice. We've tried finding one in Decathlon, Woolworth, Nanu Nana, Aldi, Müller and Lidl with no luck. Does anyone know of a physical store where I could still get a Schlauchboot today?