Community price on backpack.tf: 24.0 keys, last changed 2024-04-24 (2.5y ago). The live quote above, 22.2 keys, is 8% lower and last moved 12d ago. They are different measures: the quote is what traders and bots are asking and bidding on the classifieds right now, and it moves for thousands of items every day; the community price is a suggestion accepted by vote, which changes only when someone argues it should. A quote well away from the vote is usually a price that is about to be re-argued. Community prices from backpack.tf, read 1h ago.
Steam Market asking price: $100.11 — the lowest of one listing for the Massed Flies effect when we looked on 2026-10-11 01:31 UTC (2d ago). This is what a seller is asking, not what anything sold for. Steam pays out in Steam wallet funds, not cash, and Valve takes roughly 15% at the till — so asking prices there run well above the 22 keys, 9.88 ref shown above, which comes from the keys-and-metal market on backpack.tf. The two are different markets and are never blended. Steam lists the item as “Unusual Cold Killer”, with no effect in the name — the effect comes from the individual listing.
Price history
76 observations
Interactive chart. Press the left and right arrow keys to move along the series, Home or End to jump to either end, Escape to clear.
The key axis converts at today's rate. Prices are recorded in metal, so a line that is flat in keys followed the key rate rather than standing still.
Massed Flies Cold Killer sell price, 2025-09-25 to 2026-10-12: 76 observations, from 24.8 keys to 21.5 keys. Sampled evenly across the range.
Observed (UTC)
Sell
Buy
25 SEP 2025 · 03:29 UTC
24.8 keys
20.3 keys
9 OCT 2025 · 08:24 UTC
23.7 keys
21.3 keys
25 OCT 2025 · 16:30 UTC
21.5 keys
19.4 keys
22 JUN 2026 · 17:13 UTC
20.2 keys
17.6 keys
5 JUL 2026 · 23:12 UTC
18.6 keys
16.2 keys
19 JUL 2026 · 22:44 UTC
17.1 keys
14.9 keys
3 AUG 2026 · 00:24 UTC
21.5 keys
18.8 keys
11 AUG 2026 · 07:11 UTC
17.3 keys
15.1 keys
21 AUG 2026 · 22:09 UTC
17.4 keys
15.2 keys
23 AUG 2026 · 00:08 UTC
19.5 keys
17.0 keys
24 AUG 2026 · 06:09 UTC
14.5 keys
12.6 keys
28 AUG 2026 · 00:09 UTC
17.1 keys
14.9 keys
29 AUG 2026 · 04:09 UTC
20.7 keys
18.0 keys
30 AUG 2026 · 22:09 UTC
20.8 keys
18.0 keys
3 SEP 2026 · 06:08 UTC
22.4 keys
19.4 keys
6 SEP 2026 · 20:08 UTC
22.6 keys
19.7 keys
8 SEP 2026 · 14:07 UTC
22.0 keys
19.1 keys
12 SEP 2026 · 08:09 UTC
22.1 keys
19.2 keys
18 SEP 2026 · 10:08 UTC
13.4 keys
11.7 keys
19 SEP 2026 · 22:10 UTC
18.9 keys
16.4 keys
20 SEP 2026 · 10:08 UTC
19.3 keys
16.8 keys
22 SEP 2026 · 08:08 UTC
22.2 keys
19.3 keys
26 SEP 2026 · 02:08 UTC
22.7 keys
19.8 keys
28 SEP 2026 · 14:07 UTC
23.1 keys
20.1 keys
1 OCT 2026 · 02:08 UTC
22.7 keys
19.7 keys
2 OCT 2026 · 06:09 UTC
22.6 keys
19.7 keys
3 OCT 2026 · 11:09 UTC
22.9 keys
19.9 keys
4 OCT 2026 · 11:08 UTC
23.2 keys
20.2 keys
7 OCT 2026 · 01:08 UTC
23.0 keys
20.0 keys
7 OCT 2026 · 11:09 UTC
22.6 keys
19.7 keys
7 OCT 2026 · 15:10 UTC
23.1 keys
20.1 keys
7 OCT 2026 · 19:09 UTC
23.1 keys
20.1 keys
8 OCT 2026 · 01:10 UTC
23.0 keys
20.0 keys
8 OCT 2026 · 05:10 UTC
23.0 keys
20.0 keys
8 OCT 2026 · 11:09 UTC
23.2 keys
20.2 keys
9 OCT 2026 · 13:10 UTC
20.2 keys
17.6 keys
10 OCT 2026 · 01:09 UTC
23.0 keys
20.0 keys
12 OCT 2026 · 05:08 UTC
21.4 keys
18.6 keys
12 OCT 2026 · 09:08 UTC
21.5 keys
18.7 keys
12 OCT 2026 · 13:08 UTC
21.5 keys
18.7 keys
Price history in numbers
76 readings since 25 Sep 2025
Over the last 30 days the Massed Flies Cold Killer's sell price ranged from 13.4 keys to 23.2 keys and is up 60.0% after 40 moves. Over a year it ranged from 13.4 keys to 23.2 keys (down 4.8%). Today's 21.5 keys sits in the upper third of its range: the lowest we have recorded is 13.4 keys (18 Sep 2026) and the highest 24.8 keys (25 Sep 2025). The price has moved 75 times since we began recording it — about once every 5 days.