I'm 18 years old and going off to college next year. I'd really like to get involved in something with piano by my sophomore year, and possibly minor or double major in performance, but I need a stronger background in theory/technique. I took lessons for 9 years, then at 15 quit, and throughout most of high school had to teach myself because of time constraints and financial circumstances. With a weak background in theory as it was, I only continued to learn new pieces, and regrettably didn't continue practicing scales or theory. I need to go back and learn, but not the absolute basics. Any suggestions for books or other instructional tools that aren't extremely expensive and would be good for reviewing/learning over the summer and fall?