Shasta Daisies, white doubles not the tall growing singles ,flower for a long time and are easily propagated so you can increase your stock!
That's one that lots of people have and if you know someone who has any, your on your way!
I have just purchased, the new yellow one which are much dwarfer than the whites, they are Banana Cream, Broadway Lights and Goldrush, I already have taken a few rooted offsets of each, as they each had a few roots on they should hopefully grow!
The fancy name for them is Leucanthemum!