Boulder 850
Price trend
18 months of data shown — Listing Comps build richer history as transactions accumulate.
Sold or Listed Prices
19 market transactions via web search — not HiFi Registry sales.
Understanding the market
Half of recorded transactions fall between $4,099 and $4,500. The full range runs 3.7× from lowest to highest, which is normal for used equipment where condition, included accessories, and service history vary between units.
What buyers should know
Confirm both monoblocks have matching service histories — a pair where only one has been serviced is effectively two different amplifiers. Check that the seller has both original cartons; these are heavy and awkward to ship safely.
This range reflects 19 recorded sales, compiled from publicly listed and completed sales elsewhere on the used market, not from HiFi Registry transactions. That is a large enough sample to price against with reasonable confidence, though condition and provenance still move individual units.