Hey there! It's on a per icon basis, so if the icon you're wanting to use is from one of my paid packs, you would need to own the pack it came from. The "free packs" refer to any of my asset packs where you would receive the icon for free. So for example, the letter button icons are from a free pack so you can use those non-commercially and commercially without needing to pay.
So if you were looking to use the entire sheet in a commercial project, you would need to own icon packs 1, 2, 4, 5 and 6.
If you're making a non-commercial game though, you can use the sheet without needing to pay for the packs.
I hope that clears things up a little bit! :D