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The usefulHQ Used Price Index

What secondhand prices actually did this month, measured rather than guessed. We record the cheapest genuine listing for about 2,200 specific models every day, and this is the whole lot in one number, plus the same number for each category.

99.8
Index level, 2026-09-19. 100.0 is 2026-08-07, when daily coverage reached its current width. 2,122 models carried a price on the latest day, across 88 categories, and the secondhand market has moved -0.2% in 6 weeks.

Last 7 days -0.1%  ·  last 28 days -0.2%  ·  since 2026-08-07 -0.2%. Built from 77,214 day-to-day price pairs, of which 1,256 were discarded as changed listings rather than price moves.

By category

Projectors has fallen furthest over the 6 weeks, -15.7%. Graphics cards has risen most, +5.7%. Categories with fewer than 8 tracked models are left out because a single listing would swing them.

CategoryModels7 days28 daysSince 2026-08-07
Projectors28-0.3%-8.2%-15.7%
Acoustic guitar25+0.1%-0.2%-11.9%
Office chairs10flat-9.1%-11.1%
GoPros18-5.5%-9.3%-10.7%
Galaxy Tabs16-2.8%-4.7%-6.9%
AV receivers19-0.4%-3.6%-6.2%
PA speakers11-2.7%-1.7%-5.9%
NAS drives24-0.7%-3.5%-4.7%
Garmin watches11-0.3%-2.7%-4.0%
Blender23-0.6%-3.0%-3.7%
Stroller10-2.2%+0.7%-3.4%
Security cameras21-1.0%-1.8%-3.3%
Welders16-0.4%-1.7%-3.0%
Fitbits19-0.8%+0.7%-2.8%
Electric guitar40flat-3.2%-2.7%
Rowing machines18-1.1%-2.7%-2.7%
Ham radios22-1.8%-1.7%-2.7%
Test equipment25flat-3.0%-2.6%
Bass guitar26-0.4%-3.0%-2.3%
Air compressors16-1.5%-1.8%-2.3%
Coffee grinders23-2.0%-1.9%-2.3%
Audio interfaces25+0.1%-2.9%-2.2%
Golf clubs25-0.4%-2.4%-2.2%
Apple Watches11-0.1%-0.7%-1.9%
Camera lenses42-0.7%-1.5%-1.9%
Embroidery machines15+0.3%-1.9%-1.9%
Golf rangefinders22-1.4%-1.9%-1.9%
Gimbals16flat-1.4%-1.9%
CPUs41-0.1%-0.5%-1.9%
Guitar pedals40+0.6%+0.1%-1.5%
DJ controllers27-0.1%-0.8%-1.4%
KitchenAid mixers8-2.4%-4.6%-1.4%
Binoculars22-1.2%-1.3%-1.3%
Exercise bikes19-0.2%-0.6%-1.2%
Synthesizers40-0.6%-1.3%-1.2%
Networking gear24-1.2%-3.4%-1.1%
Pizza oven12flat-1.1%-1.1%
Camera44-0.4%-0.7%-1.0%
Launch monitors17+1.1%-0.4%-1.0%
Impact wrenches20flat-0.4%-0.9%
3D printers28-0.5%-0.6%-0.9%
Electric scooters11+0.2%+0.1%-0.9%
Digital pianos19-1.0%-0.4%-0.9%
Gaming monitor16-0.2%-0.4%-0.8%
Designer sunglasses25-0.8%-0.9%-0.8%
Microphones41-0.1%-0.8%-0.8%
Portable power stations25-0.3%-0.5%-0.7%
Sewing machine24flat-0.4%-0.6%
Designer handbag40+0.2%-0.6%-0.6%
AirPods8-0.1%-0.5%-0.5%
Google Pixel phones22+0.2%-0.7%-0.5%
Watches29-0.1%flat-0.5%
Saxophones19flat+0.2%-0.4%
Mechanical keyboard24-0.4%-0.4%-0.4%
Bench saws19-0.6%-0.4%-0.4%
Chainsaws22flat-0.3%-0.3%
Fishing reels29-0.1%-0.2%-0.3%
Metal detectors23flat-0.3%-0.3%
Sonos speakers12+1.5%+0.4%-0.3%
MacBooks40+0.4%-0.3%-0.2%
Turntable27-0.3%-0.6%-0.2%
Drones19-2.1%+1.5%-0.2%
Generators17flat-0.1%-0.2%
Robot vacuum30-0.1%+0.1%-0.1%
Camera flash25-0.1%flatflat
Film cameras42+0.6%-0.4%flat
Studio monitor41flatflatflat
Treadmills35flatflatflat
Espresso machines29+0.3%+0.3%flat
Sneaker41-0.1%-0.1%flat
Soundbars17-0.3%flatflat
Printers19+0.6%+0.4%+0.1%
Headphone29-0.1%+0.4%+0.3%
Telescopes25flatflat+0.3%
iPads40flat+0.5%+0.4%
Dyson vacuums18+0.2%+0.4%+0.5%
LEGO sets44+0.2%+0.4%+0.5%
VR headsets10flat+0.6%+0.6%
Samsung Galaxy phones40-0.2%+0.4%+0.6%
Guitar amps40-0.5%-0.5%+0.7%
iPhones40-0.1%+0.1%+0.8%
Business laptops42-0.5%-0.1%+1.4%
Cordless drills24-0.2%-1.0%+1.9%
Game consoles22+1.8%+1.1%+2.1%
Wacom tablet19-0.6%+2.9%+2.7%
Edrum kit19flat+2.1%+3.3%
Gaming laptops11+1.1%+9.1%+3.8%
Graphics cards58+2.0%+3.1%+5.7%

Download the whole index as CSV, one row per day per category, updated with this page.

How it is built

The index is chained, which means it measures each day against the day before rather than against a fixed starting month. Every model that has a price on both days contributes one ratio, and the index moves by the trimmed mean of those ratios, dropping the top and bottom 10% so one silly listing cannot swing a category.

A day-to-day move of more than 25% on one model is thrown away rather than counted. That size of jump is almost never a price change. It is the collector matching a different listing, and the reason this rule exists is worth stating plainly: a first attempt at this index, chained from a fixed August baseline, showed acoustic guitars down 32%. They had not fallen at all. Our own filters improved on 12 August and stopped pricing guitars from listings that were never guitars, so the "fall" was us getting better at our job. An index that cannot tell its own corrections from the market is worse than no index.

Prices are the cheapest Buy It Now listing on eBay US for each model, in US dollars, excluding parts, accessories, broken units and bundles as far as our filters can tell. No survey, no dealer submissions, no estimates. If a model has no price on a given day it simply does not vote that day.

What it does not tell you

It is a cheapest-listing index, not an average of sale prices, so it tracks where the floor of the market sits rather than what a typical buyer pays. It covers consumer goods that people resell online, weighted equally by model rather than by how many change hands, so a category with four models counts as much as one with fifty. And it starts in August 2026, which is a short history. Treat a one-month move as news and a six-week move as a hint, not a trend.

Free to cite. Use any figure here with a link to this page. Please include the date, since it changes daily. Suggested wording: "the usefulHQ Used Price Index, usefulhq.com/used-price-index/". If you want a category or model not shown, or the numbers behind a story, write to [email protected] and we will pull them.

Related

How much each category loses secondhand, comparing used prices with what the same models cost new. What is it worth, a lookup for one model at a time. Price drops, the models that moved most this week.