I grew up in Marin County riding my whole life (35yrs old). I've owned 25 bikes but none in the last 5 years. Just borrow buddies bikes to ride. I'm thinking if I spend $500-700 for a good used bike I can get a bike that was $1000+. I don't want anything older than 2004...What brand should I get and is ebay worth checking? My problem is I don't know anything about todays components.