Something on the ceiling would REALLY help. Drywall may be the cheapest solution if you are handy; you could also tack read breadboard up there for a cottage feel. Check out habitat for humanity restore for used and new building supplies for cheap, and craigslist also.... I found all the breadboard needed for my porch ceiling at habitat for about $50 total at a restore.

You could stain the concrete floor or paint it with floor paint in a cute design. Tile isn't TOO expensive if you DIY...the floating vinyl floors lo good and are easy to install, too..

framing and drywall would go a really long way. I'd also put in a drop ceiling instead of drywalling the ceiling. It looks as if your mechanicals ( gas lines, electrical, plumbing) run below the joists in various areas and a drop ceiling will give you access to those in case of emergencies. finally put in some $1-2 home depot tile on the floor. It will clean up the space pretty well.. Add some wire rack shelving for storage also. I don't know if you need to replace the washer and dryer or not but I'd try to get away with keeping them.