Roots Worth Tending is not a registered 501(c)(3). It's a small volunteer effort, not an incorporated charity. Contributions are not tax-deductible, and you shouldn't claim them as such.
Nobody here is paid. There's no office and no overhead — a contribution buys the thing it was given for, at the price shown, from the supplier named.
That's also why the prices are all linked. You don't have to trust the arithmetic; you can check it in about thirty seconds, and if a supplier's price has moved since a page was built, the link will show you that too.
If something here doesn't add up, say so and it gets fixed.