You can claim a free package from the shop page once every 20 hours. You may need to navigate through various sections of the shop to find the package that you can claim on a particular day.
In addition, every offer you purchase triggers a Free Sale on your shop page. The higher the price of the offer you purchased, the higher the value of the Free Sale.
Tip
Every offer you purchase triggers a Free Sale, except for purchases of Premium. Moreover, Free Sales need to be claimed after every purchase individually. E.g., if you make one purchase but forget to collect the Free Sale for it, then upon making a second purchase, you will only be able to collect the Free Sale for the second purchase.