Cool. Couple of notes - Supermarket vegies may be treated with anti growth hormones and; certified seed potatoes are disease free, the supermarket one may not be. Remember Ireland?
and you dont have to plant the whole potato. you can cut it in quarters and you should get 4 plants cause each eye on the potato is where a sprout should come out
That is true. Anything green from the potato plant is poisonous. Granted, it will take a fair amount in order to get any effects. Generally, avoid anything but the potato and the green potatoes.