You can get a nice little 6809 machine for under $30 if you shop carefully. Get a Color Computer 1 or 2 and upgrade it to 64k, they have an Editor/Assembler/Debugger called Edtasm+, it can either come on an emulated disk (using Drivewire or a CocoSDC) or on a program pak cartridge that writes results to cassette tape. Cheap, already has a bag of fun tools available, and has integrated color graphics and text using a graphics chip (the 6847) that Motorola made for the express purpose of pairing with their 6809 CPU, plus a SAM and two PIA's also made by Motorola to work best with the 6809. The only sweeter piece of 6809 candy out there would be either the Commodore SuperPet or the Mattel Vectrex. Both are awesome machines worth every penny if you can manage to find one for sale.