AAQ- Do you really think that the printers lower the cost of the siddur because someone sponsored it? I would be shocked if that were true.
Consider the seforim put out by the Chofetz cChaim Heritage Foundation. They have sponsors on every page and multiple sponsors on top of that. The books cost as much as any other Artscroll sefer.
Consider the annual Tisha Bav video. They get a gazillion sponsors for everything you can imagine and still charge $20 admission fee.