If you purchase a toy with a retail value of $15 to Knotts Berry Farm from December 5-20, you will get a voucher to get into the park for free! Also, you can buy the toy outside the park before you go in and then present a voucher for a free ticket at the main gate, so you don’t even have to buy the toy in advance.
Proof of purchase is required.
It’s not free, but it’s close to it.
Click the link for more discounts to Knotts Berry Farm 2009 and park info: