How do i meet bigfoot?

I think you get to meet him in the secret lot in the mountain vacation area.

Have a Sim use the interaction "Dig For Treasure" on the ground outside (either at home or on vacation, all though being on vacation can make matters quicker). Keep using this interaction untill you are told that your Sim has found a treasure map to a secret lot in Three Lakes. Then, when vacationing in Three Lakes, go to the lot via the community telephone. Only the Sim with the map can use the option but s/he can bring whoever they want to with them. When you arrive, you'll find Bigfoot on the lot.

cool thanks ! =)

Since we're still on the topic of meeting bigfoot, I wanna add another question:
Are you able to make the bigfoot move in with your sim's family?

1306-Yes you can once your relationship with him is built up high enough.

I also found Bigfood by going on the bird watching tour at the mountains. My sims had the map when they returned from it.