On the one published national card, a half page 4-color runs $27,710 against the full page's $44,331: 62.5% of the money for half the canvas.[1] RD Large Print sells its published half page at $11,700.[1] Below the national tier the size is quote-only, but that 62.5% ratio is the shape to expect on the cards kits send you: halves are never half price.
The half page shares its spread with editorial, which means your ad sits next to the thing the reader actually opened the book for. For response-driven creative (an offer, a coupon, a call to action) that adjacency does the work a second half-canvas would not. The buying rule at this desk: image and launch work buys the full page; measured response work starts at the half and only upgrades when tracking proves the bigger unit pays. Step 09 is how you prove it.
Cards usually price both formats the same; kits list both dimensions (sizes folio). Horizontal halves read like the bottom of an editorial page and suit wide art; vertical halves fight the column grid but own the outside edge, where thumbs land. No retrievable study on file settles which pulls better, so treat format as a creative call, not a rate decision.
Full: $44,331 / 1,400K = $31.67 CPM. Half: $27,710 / 1,400K = $19.79 CPM.[1]
Same audience either way. The full page costs $16,621 more per insertion. Unless the creative needs the canvas, that difference funds a second half-page insertion somewhere else, and frequency beats size for response.
Smaller still: quarter page. Cheaper full pages: remnant space, Step 04.