It looks like the Topps website has finally sold out of Wacky Packages Old School 5 boxes (as well as cases). This is probably because starting yesterday they offered 30% off of $14.99 a box if you bought at least $300 worth because of a Topps Memorial Day Weekend website sale (30% off of any orders of $300 or more). That means for a brief moment people could buy OS 5 boxes for $10.50 a box!
Here's hoping for a Wacky Packages Old School 6 series whether on Kickstarter or not,
Chickenfat