Community price on backpack.tf: 11.0–12.0 keys, last changed 2026-08-09 (2mo ago). The live quote above, 13.2 keys, is 20% higher 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 under an hour ago.
Steam Market asking price: $39.24 — the lowest of 2 listings for the Massed Flies effect when we looked on 2026-10-13 01:28 UTC (6h 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 13 keys, 13.22 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 Bonk Helm”, with no effect in the name — the effect comes from the individual listing.
Price history
49 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 Bonk Helm sell price, 2025-09-25 to 2026-10-10: 49 observations, from 10.2 keys to 13.5 keys. Sampled evenly across the range.
Observed (UTC)
Sell
Buy
25 SEP 2025 · 03:29 UTC
10.2 keys
8.32 keys
30 SEP 2025 · 20:14 UTC
10.1 keys
8.30 keys
9 OCT 2025 · 07:58 UTC
9.70 keys
8.73 keys
25 OCT 2025 · 16:01 UTC
8.78 keys
7.90 keys
10 NOV 2025 · 00:02 UTC
9.10 keys
8.19 keys
2 JUN 2026 · 08:29 UTC
11.7 keys
8.72 keys
10 JUN 2026 · 04:30 UTC
11.6 keys
8.25 keys
26 JUN 2026 · 11:12 UTC
7.19 keys
6.25 keys
7 JUL 2026 · 21:12 UTC
7.08 keys
6.16 keys
11 JUL 2026 · 20:44 UTC
7.75 keys
6.73 keys
4 AUG 2026 · 11:12 UTC
10.5 keys
9.17 keys
20 AUG 2026 · 14:07 UTC
10.9 keys
9.44 keys
27 AUG 2026 · 12:08 UTC
13.5 keys
11.7 keys
30 AUG 2026 · 18:09 UTC
13.0 keys
11.3 keys
31 AUG 2026 · 10:09 UTC
12.9 keys
11.2 keys
3 SEP 2026 · 00:08 UTC
12.6 keys
11.0 keys
4 SEP 2026 · 06:08 UTC
12.6 keys
11.0 keys
4 SEP 2026 · 18:08 UTC
12.6 keys
10.9 keys
5 SEP 2026 · 06:07 UTC
12.5 keys
10.9 keys
5 SEP 2026 · 18:08 UTC
12.5 keys
10.9 keys
6 SEP 2026 · 18:08 UTC
12.5 keys
10.9 keys
7 SEP 2026 · 06:07 UTC
12.7 keys
11.1 keys
7 SEP 2026 · 18:08 UTC
12.8 keys
11.1 keys
8 SEP 2026 · 10:08 UTC
13.1 keys
11.4 keys
13 SEP 2026 · 08:08 UTC
13.2 keys
11.4 keys
14 SEP 2026 · 06:08 UTC
13.2 keys
11.5 keys
14 SEP 2026 · 14:07 UTC
13.0 keys
11.3 keys
21 SEP 2026 · 16:09 UTC
12.2 keys
10.6 keys
21 SEP 2026 · 20:09 UTC
12.2 keys
10.6 keys
22 SEP 2026 · 04:09 UTC
12.4 keys
10.8 keys
22 SEP 2026 · 06:09 UTC
12.4 keys
10.8 keys
22 SEP 2026 · 08:08 UTC
12.5 keys
10.9 keys
22 SEP 2026 · 10:08 UTC
12.5 keys
10.9 keys
24 SEP 2026 · 02:09 UTC
13.0 keys
11.3 keys
24 SEP 2026 · 06:08 UTC
13.1 keys
11.4 keys
26 SEP 2026 · 20:09 UTC
12.8 keys
11.1 keys
27 SEP 2026 · 20:09 UTC
13.0 keys
11.3 keys
3 OCT 2026 · 03:09 UTC
13.3 keys
11.6 keys
7 OCT 2026 · 13:09 UTC
12.5 keys
10.9 keys
10 OCT 2026 · 23:09 UTC
13.5 keys
11.8 keys
Price history in numbers
49 readings since 25 Sep 2025
Over the last 30 days the Massed Flies Bonk Helm's sell price ranged from 12.2 keys to 13.5 keys and is up 3.0% after 18 moves. Over a year it ranged from 7.08 keys to 13.5 keys (up 46.9%). Today's 13.5 keys sits at the top of its range: the lowest we have recorded is 7.08 keys (7 Jul 2026) and the highest 13.5 keys (10 Oct 2026). The price has moved 48 times since we began recording it — about once every 8 days.