You can download Rockwell software from this link: 

(they like to change this so if so just go to - it will redirect - and go to the downloads page)

Type in: "micro starter" You should see the RSLogix microstarter lite come up in the selection list with RSLinx.

Keep in mind that if you want the english version you should pick the one with "EN" in the name. Otherwise I think you get the Chinese version. That makes my programming more difficult. You will have to create an account to download the software but it is all free. You will also need to select managed or direct download. I generally just pick direct. Both will work.