Hi,

To add sticker in e-commerce product

Odoo has a  default feature to add ribbons in products in website Shop.

To Active this,

Step 1: Activate Developer Mode

Step 2: Go to Product page

Step 3 : Select a product

Step 4: Go to the Sales Page

Step 5: In the Ecommerce Tab You can see a field Ribbon

Step 6 :You can add your custom ribbon in the field

If you Complete you can see the ribbon  in the Product Webpage

Here is the image:

Hope it helps