If you're looking for a GREAT lesson on salvation for FREE, you've got to check out this lesson from Children's Ministry Deals here.*
The skit in that lesson cracked me up -- the announcer reads John 3:16 as, "For God so loved the girls, that he gave his only forgotten son, that whosoever believes in Him would not carrots, but have eternal wife." Oh, that's classic!
And here's a fun video animation I made for John 3:16. You can download it for free, and use it to introduce this lesson: