Free dates in the summertime usually involve going to the beach. Just building a sandcastle. Watching the sun go down is a nice little sunset date. Just running on the sand and going in the water. Stealing the shovel and pail from kids, if you really want to get evil about it. But really, just enjoy the outdoors.
A free date for winter would be playing in the snow, making a snowman, having a snowball fight (but don't throw it too hard at her). Making snow angels, and then you can go inside, get your boots off and watch some TV and sip some hot cocoa. Nice and cozy.
Friends can help you get a free date - just use them as resources. You just want to just cast their possessions into your date. I know I have a friend that has a trust fund, and he has probably a swanky apartment - I'll use his apartment. And I'll borrow my other friend's car. I'll get my trendy friend's outfit, and I'll get a friend who cooks to cook for us. Your friends are your resources, and you want to definitely use those people to be cheap and be romantic.