Q: Any app i try to download it says i need to download a version of ios for every single app...how do i download ios to my ipod??

Depends on which ipod you have and which ios version you have.

Original ipod touch will go to 3.1.3

2nd gen to 4.2.1

3rd to 5.1.1

4th to 6.1.3

5th to ios 7.0.3

Identifying iPod models - Support - Apple

To update

The Settings>General>Software Update comes with iOS 5 and later.

Connect the iPod to your computer and update via iTunes as far as your iPod model allows

iOS: How to update your iPhone, iPad, or iPod touch

A 1G iPod can go to iOS 2.2 via iTunes and iOS 3.1.3 via

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

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

A 2G to 4.2.1. Requires iTunes version 10.X. If a Mac it requires OSX 10.5.8 or later.

A 3G to 5.1.1  Requires iTunes version 10.5 or later

A 4G to 6.1.3  Requires iTunes version 10.7 or later. For a Mac, that requires a Mac with OSX 10.6.8 or later

A 5G to iS 7. Requires iTunes 11.1 or later if you update via iTunes

Identifying iPod models

Hmm what generation are you using because you can only update to a certain ios before the device is too outdated and cannot go any higher also check the information tab I think it was on a app and see how new the ios needs to be to actually play it.