Some things i've found on the net that won't cost you any/much but have great possibilities nonetheless:
- People watch with a twist. Watch contruction crews at work, or athletes practicing their game, or religious people preparing for Mass.
- Go to haunted sites. Or places of not so good repute. Heck, if she has the crazy mind for it, walk where pros prowl and again, people watch with a twist.
- Arts and Crafts date. Either help make Christmas trimmings (or Valentines, since that's past), costumes, flyers, banners, etc. It can be changing her blog banner or editing pictures or just making paper stars. You can freely recycle and reuse stuff and not spend a dime.
- Read to each other. Either choose a real favorite story or anything to shock, surprise, etc.
- go on active dates like fishing, go carts, rollerblading, paintball, bike tours or hiking