Sample before you quote a flat rate
Weighing alone is not enough — a kilo of mostly 2×4 bricks is worth far less than a kilo with technic panels, printed tiles, and complete minifigs. Pull a random cupful from several spots in the bin and identify what is inside.
Note themes you recognize: licensed minifigs, old gray vs. bluish gray, and any sealed polybags still in the lot. Each category shifts value independently of total weight.
Minifigs and printed parts drive outliers
A single licensed minifig can exceed the value of several pounds of common plates. Scan or search torsos, heads, and headgear before you bundle everything as generic bulk.
Printed tiles and slopes behave the same way — a common mold with a unique print can be worth many times the plain version. Identify prints visually, then confirm against parent sets.
Build a lot description buyers trust
Replace vague titles like "10 kg LEGO bulk" with specifics: approximate mix (plates vs. bricks vs. technic), whether minifigs are included, notable themes spotted, and whether non-LEGO pieces were removed.
Photos of the sample identification — not just the pile — reduce returns and support your asking price.
Use market data as a range, not a promise
Catalog pages show recent market estimates from collector marketplaces. Treat them as guidance for negotiation, not guaranteed sale prices. Condition, completeness, and local demand still matter.
When in doubt, price rare items individually and sell the remainder as weighted bulk with clear photos of the average piece mix.