Escondido is another reasonably priced suburb. My wife and I bought a nice house there in the mid $500s. The only downside of Escondido is that the school system is not great and it's a good 40 minutes from downtown SD.
Wife and I bought a fixer-upper in old Escondido for a bit under 300. There's several tech companies in North County, and you can take Del Dios to the coast pretty easily (which is where I work).