HOW TO GET MAC APP STORE

No, 10.5 does not have the App Store.

First you need to research all the problems people are having with the higher OSX versions, & make sure you have a bootable clone of what you have just in case.

then you must get 10.6 if they still have it, install it & update to 10.6.8 so you have the App Store to buy & download the huge 10.8 Installer.

Snow Leopard/10.6.x Requirements...

General requirements

* Mac computer with an Intel processor

* 1GB of memory (I say 4GB at least, more if you can afford it)

* 5GB of available disk space (I say 30GB at least)

* DVD drive for installation

* Some features require a compatible Internet service provider; fees may apply.

* Some features require Apple’s MobileMe service; fees and terms apply.

Which apps work with Mac OS X 10.6?...

http://snowleopard.wikidot.com/

It's been pulled from the online store & Apple Stores, so you have to call Apple to buy it, last I heard.

Call Apple Sales...in the US: 1-800-MY-APPLE.

And 10.6.6 is all that is needed for 10.7, if you install straight from the App Store. 10.6.8 is only necessary for 10.8. Read these tips about 10.6:

https://discussions.apple.com/docs/DOC-2455

10.7 https://discussions.apple.com/docs/DOC-2465

and 10.8: https://discussions.apple.com/docs/DOC-3761