MegaMacs offers dealmac users the OEM Mac OS X 10.6 Snow Leopard (pictured), model no. MC223Z/A, for $26.99. With free shipping, it's the lowest total price we could find by $2. This single-user upgrade, which includes the contents of the retail box but not the box itself, is required to upgrade to OS X 10.7 Lion.

MegaMacs also offers the OEM Mac OS X 10.6 Snow Leopard Family Pack, model no. MC224Z/A,for $44.99. With free shipping, it's tied with our August mention and the lowest total price we could find by $4. It installs on up to five Macs. Both deals end November 1.