With most mail, the only question is whether it arrives. With tax and legal documents, there is a second question that matters just as much: can you prove you sent it, and when.
Those are different problems, and postage solves only the first. Here is how to handle both.
Postage first: get the weight right
Tax packets are heavy. A return with schedules, a statement run with inserts, a legal notice with exhibits — these cross ounce boundaries in ways that catch people out, and short-paid mail comes back to the sender rather than going forward.
Weigh one representative piece from each batch rather than estimating, then apply that figure across the run. Where a packet needs more than one ounce, use the correct denomination — additional-ounce or two-ounce stamps — instead of stacking Forever stamps to reach a total. Rigid or oversized envelopes need a non-machineable surcharge stamp.
Current figures for every class are in the USPS Notice 123 price list.
Proof of mailing is a separate purchase
This is the part people miss. Ordinary First-Class postage carries no evidence that you mailed anything.
For filings with a deadline, the services that generate a record are what you actually need:
- Certificate of Mailing — proof you handed it over on a given date. It does not prove delivery, and for a deadline that is often the only thing at issue.
- Certified Mail — a mailing receipt plus a delivery record retained by USPS.
- Return Receipt — the recipient's signature returned to you, when you need to prove someone actually received it.
Each carries a fee beyond postage. For anything with a statutory deadline attached, that fee is the cheapest insurance on the transaction.
Best deals on Forever stamps
What an auditor actually asks for
Postage bought for a business is a deductible expense, and like any other it needs a paper trail. The standard is not complicated, but it is specific.
You want a commercial invoice from a supplier with a verifiable US business address and a tax ID, showing quantity, denomination and price. That reconciles against your mailing logs and stands up on review.
What does not stand up: a personal payment app transfer to an unnamed seller, with no invoice. Even if the stamps were genuine, there is nothing to file — and an expense you cannot document is an expense you may not be able to claim.
Why the cheap stamps are a compliance problem, not just a quality one
Genuine stamps carry phosphor tagging that sorting equipment verifies on every piece. Untagged stock is pulled from the mail stream rather than delayed.
For tax documents that changes the nature of the failure. A missed deadline caused by seized postage is not a shipping inconvenience — it is a filing that did not happen, with whatever consequences attach to that. And the proof-of-mailing receipt you bought does not help if the piece never entered the stream properly.
Genuine secondary-market postage supports a discount of roughly 10–20%. Past that, you are buying a compliance risk at a discount to the postage.
A workable routine
- Weigh a sample from every batch and record the figure alongside the job.
- Buy proof services for anything with a deadline, and file the receipts with the job, not in a drawer.
- Keep invoices for postage purchases with quantity and denomination itemized.
- Reconcile quarterly — stamps bought against pieces mailed. Unexplained gaps in a busy office are usually shrinkage, and worth finding early.
Where to buy
Full price with no ambiguity: the USPS official store. Bulk at a defensible discount with proper invoicing: a specialist such as Forever Stamp Center. For an urgent local drop, the USPS location finder.
Background worth an hour if the subject interests you: the Smithsonian National Postal Museum and USPS postal history.
The short version
Weigh it, use the right denomination, buy proof of mailing when a deadline is involved, and keep an invoice you could hand to an auditor. The postage is the small part; the record is what you will be asked for.
More on buying Forever stamps
- 👉 Why Tracking USPS Stamp Orders is Crucial for High-Value Business Buys
- 👉 Understanding Delivery Times: Priority Mail Stamps vs Forever Stamps Rules
- 👉 Verifying Authenticity: Sourcing Bulk Postage for Direct Mail Campaigns
Stamp enthusiast and part‑time columnist based in Los Angeles. With a background in office administration and a personal passion for collecting Forever Stamps, she provides readers with practical tips on buying, storing, and using stamps effectively.
