Hi,
There isn't really any discount like that. Magix software is already much much less than other products in its class. The best thing to do is purchase the download version of the product - it's a little less.
Keep in mind that MM12 is the last FULL version at that price point. To get MM14 with the same features will cost more. They've split the product line into two versions. If you must upgrade I would suggest Samplitude Music Studio. Music Maker is not really a good upgrade path anymore - stick with 12 or make the switch to Samplitude.
Justin