Everything needed for this bin (except the super cute shamrock care bear, we've had that for years) can be found at Dollar Tree. As for the addition of a St Patrick's day stuffed animal I'm sure you could find a Beanie Baby of something of the sort. All you need is a pack of construction paper, and some gold coins.
Just rip up the construction paper (one piece per color of the rainbow) into squares and arrange them in a row in a sensory bin. Add in the stuffed animal or whatever you're putting in the middle of your bin, and then place some gold coins around it.