You are going to buy for $15 an old copy then upgrade for $6 to save buying a $19.95 program.. Sounds like a lot of trouble to spend an additional $1.05.
The idea behind buying the CD is so I have a physical copy and all I have to do is upgrade for $6.
I was going to buy gold fish aquarium 1 for $1.99 on ebay then buy the upgrade. But I saw someone selling marine Aquarium and goldfish aquarium for $15 so I decided I would rather just buy both. Since I did see marine aquarium on youtube and I wouldnt mind having a physical copy of that. I hope thered upgrades to it I can download.