One afternoon last week, a single keyword cost me $4.37 in ten hours.

Not a typo. One keyword, #buildinpublic on X, at the X API's pay-per-use pricing of half a cent per tweet returned. The hashtag produces roughly ninety posts an hour, my poller dutifully fetched all of them every hour, and by evening I'd bought 868 tweets I mostly didn't need. Annualized, that one keyword was on pace for about $360 a year. For one keyword. On one platform.

That incident sent me down a rabbit hole I should have gone down earlier: what does it actually cost to know when someone mentions your product, your competitor, or your problem space on the internet? The answer turns out to be "anywhere from $0 to $4,800 a year," and the difference is almost entirely architecture, not features.

The menu, honestly priced

The suites. Brand24 starts around $199/mo billed annually; useful tiers for a team run $300–600/mo. Mention has moved upmarket. Its cheap self-serve tiers are gone, and its remaining plan starts around $599/mo billed annually. These are real products with real breadth: news, blogs, podcasts, TikTok, sentiment charts, PDF reports. If you're a brand team that reports share-of-voice to a VP, they're correctly priced. If you're a founder who wants to know when someone on Reddit asks for a tool like yours, you're buying a combine harvester to mow a balcony.

The alert services. Syften (~$30–120/mo) and F5Bot (free tier; paid tiers from ~$17/mo) watch Reddit, Hacker News, and niche communities and email you on keyword hits. Honest tools, honestly priced. Their limit isn't coverage. It's that an alert is the start of your work. Judging and answering 50 alerts is still your evening.

The APIs, raw. This is where it gets interesting, because the platforms have wildly different philosophies:

Reddit is effectively free to monitor if you go about it politely, no suite required for the same community data. For watching specific subreddits, it's the best value on the menu.
Bluesky is free, full stop. The AT Protocol's search endpoint is open, unauthenticated, and rate-limited generously enough that no startup will ever hit the ceiling.
X bills per resource: $0.005 per tweet read. Sounds tiny. Isn't. Per-resource pricing means a busy keyword is a money pump. My $4.37 afternoon was the pump working exactly as designed. (Posting is worse: a plain post is $0.015, but a post containing a URL is $0.20, a 13× surcharge on the one thing a marketer wants to include.)

Cost is an architecture problem, not a feature problem

After the $4.37 afternoon, the lesson was simple: with per-resource pricing, what you pay is decided by how you poll, not by which vendor you buy. Drain a firehose hashtag and you pay for every post in it. Pull only the newest slice and score it hard, and the same busy keyword costs cents. The teams getting billed $360/year for one keyword aren't being overcharged. They're fetching everything when they only needed the freshest few.

That's the whole game on the raw-API path: pull less, score harder. A monitoring layer built around that keeps a worst-case firehose down to a few dollars a month; one that drains everything turns a half-cent-per-tweet price into a money pump.

What you should actually pay

My honest decision tree, having now lived all the branches:

Pre-launch, zero budget: F5Bot for Reddit/HN, done. Free, five minutes of setup.
You want broad web/news coverage and PR metrics: pay the suite. That's what they're for.
You're a founder whose buyers live on Reddit, X, and Bluesky, and you want mentions to end in sent replies rather than dashboards: the monitoring layer should cost you almost nothing (Reddit and Bluesky are free, X is metered per tweet, so you cap what you read) and your money should go to the layer that turns those mentions into replies and customers: scoring, drafting, and the daily queue that lands them.

The mention firehose is a commodity in 2026. Anyone who charges you suite prices for the firehose alone is charging for the part that's free.

Thread Otter is that second layer: it scores the firehose, sends the replies in your voice from your own account at a human pace, and hands you the receipt for which one became a customer. Free for 7 days, no card.