Watching movies or shows together, walking along the beach (if you live by one), a swim at the lake, laying in the grass watching the sky together or something, playing in the rain, I love free dates more than I love payed dates.
One time I didn't have much money. In fact i had just spent the money on going to the night club where I ended up meeting the young lady who asked me out on a date, and she asked me what I wanted to do and where I wanted to go after I agreed to go out on this date with her. I thought about it and decided that we should go to a field - provided that it was not raining - and buy two boxes of pizza, and just watch the traffic go by and the lights of our small town as we got to know one another and bonded in nature. It was pretty amazing.