About / focused seller economics
Small tools for expensive decisions.
MarginTally is being built to answer a narrow question well: does this product, price, or ad target leave enough money after the costs that matter?
Why this exists
Marketplace dashboards report activity. Seller spreadsheets hold assumptions. MarginTally connects the two with transparent formulas that can be checked line by line.
This LIMITED MVP contains five calculators for US-dollar decisions. It avoids broad marketplace coverage until the fee data, maintenance load, and seller usefulness of the focused set are proven.
What it does not claim
MarginTally is not a bookkeeping system, tax engine, payout reconciliation service, or substitute for platform statements. It does not tell every seller what margin they should accept.