There will be (4) inserts. You should get (1) P&G, (1) Smartsouce, and (2) Red Plum. I find that in my area, when I am supposed to get 2 Red Plum, they are typically combined into one, so you may get some of the coupons from both in 1 insert.
There are variations by region, so plan on buying the largest paper in your area. If you are unable to get a great paper, there are several alternatives. One that I recently found was Whole Coupon Inserts. I have not personally tried it, but would love to hear some feedback if you have. You can also shop The Coupon Clippers and other clipping sites.
Previews courtesy of Coupon Previews on WeUseCoupons.
Red Plum #2
P&G (all expire 8/31)