I am currently running Mac OS X 10.5.8.

I would like to install a program that requires Mac OS X 10.7 or later.

I am looking for the cheapest/easiest way to accomplish this.

It has been a while, obviously, since I have updated my operating system and I am thus a little out of touch.

Any help would be appreciated.

It would be helpful to know what Mac you are using and it's processor, RAM, etc. to properly answer your question.

I'm using a Black MacBook, Intel Core 2 Duo, 4gb RAM

You need to purchase Snow Leopard here first: Mac OS X 10.6 Snow Leopard - Apple Store (Canada) (http://store.apple.com/ca/product/MC573Z/A).

Then buy Lion from the Mac App Store (digital download) that comes with OS X 10.6.6.+

You can buy 10.7 on a USB stick from Apple !

You can buy 10.7 on a USB stick from Apple !

Requires OS X 10.6 to be preinstalled.

Requires OS X 10.6 to be preinstalled.

Yes, and no. To upgrade you need to have Snow Leopard preinstalled. However, you can do a backup (Time Machine) of your current system, do a clean install using the Apple USB stick (or home made one) and then use Migration Assistant to move everything back from the backup.

The 10.6 / 10.7 route is the way to go. The Mac App Store Lion download is the cheapest way as the Thumb Drive is twice the price. The download is 3.75 GB, which I ran overnight. You can use the download to create a bootable DVD or USB prior to installing.

How to make a bootable Lion install disc or drive | Macworld (http://www.macworld.com/article/1161069/make_a_bootable_lion_installer.html)

Note, if you have any old PPC only apps they do not run under Lion. I lost my old TaxTron files, but did manage to back them up and pdf them prior to upgrading.

Requires OS X 10.6 to be preinstalled.

You can install a new drive HDD with nothing installed and boot from the USB stick and install it which I have done!