Set up a separate e-mail account, and sign up for e-mail lists for everything. Companies love marketing through e-mail and will often give you free stuff in exchange for that opportunity.
There’s a group of locals in my neighborhood who are on mailing lists for all the wine shops. Most wine shops have tastings on weekend evenings because that’s when people are out and about. There are usually four or five wines at a time. These folks go from one store to another and get hammered for free. I should be mad, because they never buy anything, but… it’s brilliant!
Most stores have some sort of e-mail list where they post their best sales and offers. A lot of these will give you rewards for tracking your purchases, something on your birthday, etc.
I also like belly bites. It’s a loyalty card/ app that tracks the bejeesus out of your purchasing behavior, but they send offers for free drinks and appetizers and stuff by e-mail.