Left over tags are first come first serve. They go on sale on the internet on a cretin day and time on DFG website. Some are gone within minutes and others dont sell out at all. Most leftover units will have some access issues. Just do some research on public land and access to it before you buy a tag and be sure to get good maps and a gps with a chip because the land ownership boundaries are generally poorly marked if at all. I have found the preview maps on mytopo.com are a good place to start to get an idea how much public land a unit has to start narrowing it down.