The table below gives you an overview of the dos and dont‘s of each license attached to the premium icons.

Personal
Commercial
Extended
Can I remix, transform or modify the icon?
Yes
Yes
Yes
Can I use the icons for commercial use?
No
Yes
Yes
Can I use an icon as part of a logo or other trademark?
No
No
No
Is there a limit to how many icons I can use per project?
Unlimited
Unlimited
Unlimited
On how many end products for sale I can apply the icons?
0
5,000
Unlimited

The freebies are under CC BY 4.0 Deed license.

That‘s pretty much it. If something is unclear, dive into the documents below.