Disappointingly, the Apple Store (both online and brick and mortar locations) no longer carries v10.6 (Snow Leopard) or 10.7 (Lion) for sale or download, which is required before updating to Mountain Lion. So, it's almost as if a loyal Apple customer like myself has been abandoned to antiquity. However, after going into my local Apple Store today, I was told to check out Amazon.com or Best Buy to order the software.
BUT WAIT! On Amazon, it is being sold for an average of $80 - $90; also, if you buy an "open box" version, it has been reported in customer feedback on Amazon that instead of an original disk, sellers will send a memory stick without any guarantee or instructions. So, I don't think I'm willing to spend around 3x the amount of what Apple was likely to be selling it for, or risk some bizarre or problematic installation using a memory stick.
Here's how I resolved it today:
I called Apple Care at 1-800-275-2273.
I needed my Serial Number for my device/laptop.
I told them that I was stuck from upgrading to a more current OS as delivered straight from Apple, instead having to settle for a 3rd party who charges a lot, and if used, with no guarantee of receiving a valid disc or software.
The Rep was super helpful and friendly, and offered to send me (for FREE!!) the discs for Snow Leopard or Lion to my address next week! Yippee!! And, I didn't have to pay for the support call as my Apple Care coverage had run out. WIN!!
Hopefully, engineers will read this and realize that they're leaving Leopard folks in the dust and maybe with a bad taste in their mouth since there's no way to directly upgrade from Apple. It would be SUPER helpful if one or the other of 10.6 or 10.7 were still available online for download!!
Hope this helps!