plywood floor...think it would look great with a dark stain on it, then poly
How to make your own plank floors (We did this in our bedrooms... very inexpensive and simple)
Google Image Result for http://www.designshuffle.com/blog/files/2012/01/1-Tile-Floors.jpg
Hometalk | I Made an End Grain Wood Floor From Scratch and Saved Myself $4000!
Painted Concrete Floors would be great for the unfinished basement
Hand #painted #floors in the style of David Hicks in designer @Grant K. Gibson dining room at the San Francisco Decorator Showcase 2011.
50 Painted Floors Inspirations | Shelterness
Inexpensive solution for flooring: painted pattern directly onto the subfloor. It is sealed with poly and has held up very well, even with two young boys.