If you're looking for the ultimate sub 3" folder with a $300 limit, then I'd say look around for a small Sebenza. It'll last you a lifetime, then you can get it refurbished & have something to pass on to one of your kids.
Otherwise, I'd probably look at the Kershaw mini-Cyclone ZDP, maybe a Bradley Alias II, or even a Spyderco ZDP Delica.