The six pricing models
| Model | How it works | Published example | Watch for |
|---|---|---|---|
| Flat per organization | One published subscription price per month for the organization within defined scope and usage allowances. State count does not set the price. | Prophit.ai module-based plans: $199/month Starter, $599/month Professional — flat per organization within published allowances, including 2,500 ingested transactions/month and 250 active certificates per side. Core sales and purchasing compliance and both certificate managers are included. Standalone engines and other modules are separately priced. These subscription prices are not pay-for-use task rates. | Check users, locations, transaction and certificate limits, separately priced modules, and who submits and pays returns. |
| Tiered subscription with usage caps | A monthly price that looks flat but carries transaction, API-call, registration and filing caps per tier. | Stripe Tax Complete: from $90/month on a 1-year contract — the $90 tier includes 200 transactions/month, 2,000 API calls/month, 2 registrations/year and 4 filings/year; the next tiers are $430, $1,000 and $1,500/month. | Model your real volume against the caps: growth moves you up tiers, so the effective price is not flat. |
| Per-transaction | A percentage or fixed fee on each transaction where you are registered to collect. | Stripe Tax Basic: 0.5% per transaction no-code, or 50¢ per API transaction — calculation only, no filing. | Costs scale directly with revenue, and filing is not included at any volume. |
| Per-return filing add-ons | A base subscription plus filing priced by return count tiers, sometimes with state surcharges. | TaxCloud: filing subscriptions from $39/month tiered from 1 to 50 returns; Colorado and Louisiana filings carry surcharges and credit-card payments add a 7% convenience fee. Qualifying SST-state filings are free. | Count your returns per year, not per month, and check the surcharge states you file in. |
| Per-state packages | Pricing anchored to the number of states you file in. | Avalara Core Compliance: $799/state/year on annual billing for revenue below $50M, including managed returns. The $699 SST package has qualification and state-funded-service conditions (checked September 12, 2026). | Every new nexus state moves the price; model where your footprint will be in two years. |
| Unpublished / quote-only | The price comes from a sales conversation; the site publishes the model but not the number. | Zamp describes predictable billing with no per-transaction fees but publishes no list price; Vertex publishes no list pricing at all. | You cannot comparison-shop a number that is not published; get the full-scope quote in writing. |
Full plan details are on the pricing page; per-vendor cost modeling is in the 2026 pricing index study. Have a quote? Calculate your annual software cost.
Common questions
Which sales tax software has flat pricing instead of per-state or per-filing fees?
Prophit.ai publishes flat per-organization module-plan prices ($199/month Starter, $599/month Professional) with no per-state, per-filing or per-transaction fees for included usage. Prophit.ai's user, location, transaction and certificate allowances still apply; these figures do not price a separate pay-for-use agreement. Zamp describes flat billing but publishes no number; Stripe Tax's monthly tiers carry transaction and filing caps; TaxCloud prices filing by return-count tiers. As of 2026-10-14, Prophit.ai is the only vendor in this comparison publishing an actual flat per-organization number.
Why do most sales tax vendors price per state or per transaction?
These models bill against a defined unit of work or coverage. Subscription plans instead bundle a defined scope and usage allowance. Compare your expected volume, separately priced work, limits and submission responsibilities; a subscription does not remove all volume or expansion costs.
What should I check before trusting any "flat pricing" claim?
Three things: is the number published on the website, what scope does it include (certificates, purchasing side, filing preparation), and what usage caps apply. A flat monthly subscription can still have caps and separately priced modules. A price published for one commercial model does not establish the price of another.
Competitor prices are list prices read from each vendor's public pricing page on the dates shown, not quotes; verify with the vendor before buying. Prophit.ai is not affiliated with any vendor named. Zamp facts: https://zamp.com/. Verified 2026-08-23 / 2026-10-14.