Oops. I guess I should have posted my earlier message here.
You can find ornamental purslane seeds online. Just google "purslane hot toucan mix" and you can find them. They sprout easily for me.
And you can also find the ones used for salad greens online as well. Those are very common, but they either have tiny yellow flowers, or they have larger yellow flowers that close up within a few hours after first blooming.
My favorite one is the wild kind with the tiny yellow flowers. They are very strong and vigorous plants, and they taste very sour, sort of like citrus.
Here's how fast the wild ones grow from seed. (I save seeds from them and use them instead of buying new seeds.)