I agree. Commercial shuttle services between trailheads run about $100 per person, if not more. Paying $20 for a lift still saves you a bundle.

When hitching between trailheads, I make sure I have at least rinsed out my clothes recently, take a dip in a stream, and look presentable. If you stash your pack you often will get a ride sooner. You can come back and pick up your pack. People with small cars usually have limited space and do not want a dirty pack in the back seat (or a dirty hiker!). Also it is a lot more successful if you simply ask people in the parking lot at the trailhead. Often I see hikers but there is no safe place to pull over.