You can make an endless supply of manipulatives very quickly by using the "Drag a Copy" feature. Just right-click on the object and choose "Drag a Copy" from the menu.
Similarly, you can select an object and go to the "Property Browser." Scroll down to the "Miscellaneous" section and turn "Drag a Copy" to "True."
When you hover over the image, you will now see a hand and green plus sign which shows you can drag a copy.