Everyone with a premium Sales Navigator has the recommendation option in the top right corner. You can send an invitation there, through which your friend gets the premium version free for two months.
This only applies if the person has not sent more than ten such recommendations. And it does not apply if the recipient has used any other free premium service in the last 12 months.
In any case, remember that even the free premium version will require you to enter a payment card, and if you do not cancel it in time, a fee will be charged from the third month.
It is a nice way to save about 200 EUR and find out how powerful Sales Navigator Core is when used correctly.
Bonus trick: after 58 days, cancel the premium version. LinkedIn will ask you why you are canceling and claim it is too expensive. They will offer you another two months at a 50% discount.
If I were the owner of LinkedIn, I would do the same. This premium pays off for most demanding users and you get used to it, and you will be fine with its price. Then you purchase an annual subscription with an additional 33% discount.
Note: This article contains the most common behavior of this network in August 2023. However, different rules may apply for your account.