Confusing Fee Structure.
What? The $87 for 18 months membership? It's no "special deal," it's just more convenient because you don't have to write two checks.
As a new AMA member, if you join between July 1, and September 30, you have to pay the full $58, but you get 1/2 year's credit toward next year's dues. It's ALWAYS been this way.
$58 + $29 = $87