Right now on Zulily.com they have a ton of puzzles for under $14. Even with shipping everything should stay under $20.
These do NOT look like puzzles for the faint of heart!
Shipping starts at $5.99 and generally goes up $1- $2 with additional items. Consider making one order, and then go back and order another item and shipping should be FREE since they offer free shipping for almost all additional items ordered by 11:59 PM that same day. Some larger items may be excluded for the free shipping offer.