The Alternate Method of Entry (AMOE) is the mechanism that keeps a purchase-linked promotion out of lottery territory. If you let people enter by buying a product, you must also offer a genuinely free path — an online form or a mail-in — that gives free entries the same odds, the same deadlines, and the same number of entries as any paid path. This is the "equal dignity" rule, and it is summarized in the federal baseline.
Equal dignity is the part promoters get wrong. A mail-in that requires a stamped envelope, a hand-drawn postcard, and a two-week delay is not equal to a one-click purchase entry. The free path has to be a real, usable alternative, not a trap. Document it clearly in your official rules so the free method is as prominent as the paid one.
A prominent "No Purchase Necessary" statement is the visible half of the fix — required for mailed materials under 39 U.S.C. § 3001 and for digital promotions under the FTC's Dot Com Disclosures guidance. Pair the statement with the AMOE so an entrant can actually find and use the free path. The compliance checklist walks through both disclosures.
In Canada the structure is similar but the free-entry requirement is paired with a skill-testing question (STQ): a simple math or general-knowledge question the winner must answer so the prize is not awarded by pure chance. The Canada notes detail the Criminal Code test and the Quebec exception created by Bill 17.
Bottom line: if a purchase is one way in, a free way in must exist on equal terms. Get the AMOE right and the promotion keeps its sweepstakes status; get it wrong and you have built the third element of a lottery.