County and municipal agencies in King County, Washington sell surplus through online auction sites like GovDeals and Public Surplus. BidProwl tracks all of them in one place: 378 live lots right now. Register on the platform hosting the lot you want; most items are local pickup only.
The usual mix is retired fleet vehicles and police cruisers, public works equipment, school district electronics and furniture, and unclaimed or seized property. Inventory refreshes daily as agencies list new surplus.
364 live auctions across King County right now.

Federal Way, WA · GovDeals
6d 1h left · 39 bids
$2,325

Bothell, WA · GovDeals
3d 5h left · 39 bids
$2,000

Federal Way, WA · GovDeals
5d 4h left · 28 bids
$9,900