I emailed Valvoline once a few years ago asking for oil change reminder stickers and also Valvoline decals for my collection. They never sent me any Valvoline oil change stickers but they did send me a big envelope with about a dozen Valvoline decals of various sizes. It took about a month for me to receive them in the mail but I was very glad they did send the decals.
Around that same time, I stopped by a local garage that had a Valvoline oil change sign out front and they gave me a roll of about 50 Valvoline branded oil change reminder stickers. They said Valvoline sends them to the shop for free. The guy peeled the stickers off a roll that had to be a good 10 inches in diameter and said "here ya go".
I had no such luck though when I emailed SOPUS asking for Quaker State branded oil change stickers and decals. If I could find a QS oil change place I would ask them for some QS reminder stickers, but now I just use the free ones from AAP. I like those better anyway because they seem to hold up better in the sun and they have more room to write on, and I can write the date and mileage of my next OCI in larger and darker letters so I don't have to squint to read it after it has been on my windshield for a while.