What I meant, though, is it's a lot more work to change a car from FI to a carburetor than you think it is. besides having to find an intake manifold and carb, you'll need to source all the little bits and pieces like fasteners, springs, etc. FI cars also use an electric fuel pump to deliver higher pressures than a mechanical pump can provide and also have a return line to send excess fuel back to the gas tank. There are probably many other parts that will be different between FI and carburetted models as well. You'll probably end up spending enough on the conversion to buy 3 computers.
here's a recent classified ad
http://ottawa.kijiji.ca/c-cars-vehicles-parts-accessories-1975-VW-Beetle-ECU-Fuel-Injection-parts-W0QQAdIdZ47282401
$50 and probably something for shipping for the ECU and assorted other FI parts. I don't consider that unreasonable compared to the cost of doing a conversion. You've probably spent more on Mac parts on ebay.