I use a small scale I was given it tops out at 11 lbs. I use a bathroom scale (when my wife isn't looking) for my buckets.
Vehicles I use a 2002 Ford Windstar minivan or my '94 Honda Accord.
I'd also echo what Sirscrapalot said about having business cards to hand out. I work closely with my local sheriff's dept, I'm a hazmat tech and they are really...ah...sensitive about anything that can possibly be construed as "paraphernalia" to the point of ridiculous.