when I started I made the mistake of building bikes from used bikes and wound up with a big mish-mash in my basement of working and semi working bikes that I had to eventually clear out. you might be better off going to a used bike clearance house / bike exchange /used bike shop, etc and buy something appropriate for yourself that is ride ready and give them what you have

this is the place I was remembering and should give you an idea. where do you live?
http://www.cambridgeusedbicycles.com/

http://www.yelp.com/biz_photos/cambr...es-cambridge-2