Q: where can i purchase the ios 3.1 software update for ipod touch

iOS is free.

Connect to iTunes on your computer to update.

How to update your iOS device

Scroll down to the “Update your device using iTunes” section

Axeman1020, not ture, the last update for the 1G iPod, iOS 3.1.3, is a paid update that you get here:

Purchasing iOS 3.1 Software Update for iPod touch (1st generation)       

https://buy.itunes.apple.com/WebObjects/MZFinance.woa/wa/touchLegacyLandingPage

That is the only paid iOS update

Thanks lllaass!