If you can wait, keep an eye on Apple's refurb site. I've seen their lower memory (32G?) iPhone 7 for $379, but they disappear quickly. Also remember that the Apple refurbs have a new shell and a new battery along with their 1 year warranty.
The Best Buy/Walmart/Target deals always require a contract with a big carrier. Since I have a cheap MVNO plan, buying the phone outright ends up cheaper for me.
I went from a 4S to a 6 (same size as the 7 and 8), and while I was concerned about the size, my eyes really appreciated the extra screen real estate. Unfortunately, my 6 has developed a hardware problem after almost 4 years, and I'm on the lookout as well.