Legacy Lens for Lumix G3

Hi there!

I'm a newbie who just got into photography for a few months after receiving a Lumix G3 as a present.

Now I'm trying to learn how to shoot with manual focus and I want to get started with some legacy lens.

Can you guys recommend some cheap legacy lens that are suitable for a student budget and are easy to get started with?

I have been looking at some discussion topic but could not find any recommendation for G3, would there be any specific lens that go well with G3?

I'd really appreciate your help.