What is the cheapest way to get Microcontrollers? Well desolder them from other boards is often quite cheap. A suitable Controller is also on the MMMR-70 radio Modules. I bought ten of them some time ago (see #Yet another MMR-70 project). And for 0.7€ you can not get a new ATmega32.
You should only take care about the fuse settings of the controller. I did reprogrammed them to default before desolder the ATmega from the MMR-70 board.