I'm with Crooketarrow. I've pulled branches out of piles the park dept cuts down (yew, hackberry, purple leaf plum, laurel, scotchbroom, hawthorn) stalked the tree trimmers in the neighborhood (dogwood, hornbeam, purple leaf plum, incense cedar, juniper) just asked neighbors (juniper, black locust, hazel, laurel) and cut vine maple, yew and ocean spray when I'm camping. I have my eye on a small plot of land in the middle of the city that has lots of hawthorn and locust trees that is slated for development and the bulldozer.
I have enough wood to last for the next 4 years at the rate I work and it hasn't cost me a dime. I finally stopped gathering (which is kinda one of the funnest parts of bowyery for me) I gotta stop collecting or start trading for stuff, I'm out of room.
Helps to live in a place like Seattle but bow wood is everywhere, in abundance, even in the bay area (hillside covered with oak and laurel). You just got to learn to ID it and know what you're lookin at and read up on whether it is a good bow wood or not and try em all.