Must one get written permission to promote other people's products?

[Mistica]

I have my own products and store so that makes me an affiliate / associate as well.
If I wanted to earn the extra 15%  by selling other people's products as well as my own, it that illegal? 

I know if I search well enough I can see that people are selling my products.

I am very fine with it...but just wonder what the latest rules are.

[SJoy]

You can add your referral code to the end of any page on Zazzle for promoting.  Here is a link to the How to build Referral Codes section: https://help.zazzle.com/hc/en-us/articles/115002533768-How-to-Build-Referral-Links

It says: 

Zazzle's Associates Program allows anyone with a Zazzle account to earn referrals by promoting Zazzle on their personal blog, website or social media site.

You can link to any Zazzle pages including product pages, search pages, store categories, and even this page using your unique Associate ID.

Also, you don't have to ask for permission to promote someone else's product and appending your referral code to it.  If they make a sale off the product you referred then you get the percentage for being the "referrer".

[PenguinPower]

Goodness no…  you can promote any products on the platform. If designers want to be exclusive they can keep their products set to direct only. 

Anyone who wants to can feel free to promote my products as much as they like.

[Mariholly]

You can promote any product from any designer, so both you and the designer earn profits. In fact, some fellow creators have blogs for that purpose and ask us to showcase our best products. Feel free to promote mine if you wish 😉