Ending today, A4C offers the OEM Apple 60-watt MagSafe Power Adapter for MacBook, model no. MC461LL/A, for $34.95 with free shipping. (Accxpress via eBay offers it for the same.) That's $32 below our mention from last fall and the lowest total price we could find by $2, although some major stores charge around $75. It's designed for the MacBook and 13" MacBook Pro.
Note that it ships in bulk packaging and does not include the AC extension cable wall charger.