California - Cheap parking in downtown San Diego

I will be staying at the Westin Horton Plaza and the W but don't want to pay the >$20/day for parking. Anyone know of any cheaper alternatives in that vicinity?

I think you can park in the horton Plaza garage for less than that. Maybe its closer to $10. A few blocks away down G street and some other side streets there is "free" street parking. My friends often find sports--the one catch is you need to move it by 9 am....so it works for overnight.