Buy two and get a third for free. Not too bad of a deal.
These boxes are quite nice to have. Don't just take it from me. CrossRoads will vouch for these "really useful boxes" as well. I have a ton of them and still run out of some sizes. I'm hitting the store tomorrow for some more. Been busy with raspberry pi lately (need more boxes for the pi, note to self).
Just came back with 9 boxes. If you want to get this deal, you have to check out 3 same boxes at a time. If you get say 3 large ones for $7 each and 3 small ones for $2 each then you won't pay $72+$22= $18. You will pay $7*2 +$7+$2=$23 because they only make the least expensive ones free!!!
Officeworks here in Australia are carrying them. Might check them out over the weekend.