The reason to put an object in a mailer is simple: an envelope with something in it gets opened, and a flat one often does not. The trade-off is that postage, not the product, sets your budget — and the two are linked in a way that catches people out.

Thickness costs more than weight

Postal pricing punishes anything that will not go through automated equipment. A quarter-inch of extra depth can move a mailer into a higher class and add more per piece than the item itself cost. Magnets, sticky notes, cloths, flat cards and slim tools are the categories that survive this; anything with volume needs the postage costed before you commit.

Take a sample to the post office or your mail house and get the actual rate before ordering thousands.

Magnets are the workhorse

They rank at the top of every direct mail list and it is not sentiment. A magnet is flat, cheap, survives the machinery, and ends up on a fridge with your phone number on it for years. For service businesses — plumbing, dental, veterinary, real estate — nothing else in this price bracket produces the same recall.

The item is not the offer

A gift in an envelope buys attention for about four seconds. What converts is the offer printed alongside it. Do not let the novelty of the object stand in for a reason to respond — put a real one on the card, with a deadline.