I use only name brand fuel of the recommended octane. 89 for my ram before tuning, 93 octane now. I have gone to the Royal farms near the track for a few gallons when racing late in my Charger( because I was WINNNING!) and the results were poor, ran slower and more knock. Cheaper is not always the best idea. then again My closest Sunoco, unfortunately, has given me bad gas on more than a few occasions. First in my Charger, which took me awhile to figure out, as I would get gas there on the way to the track and not run as well as I should have. In fact I ( well actually Sean) didn't figure it out until I was data logging for Hemifever. he told me it looked like I was buying cheap gas. I switched to BP and Walla all is well.
SO I avoid that particular station, but not Sunoco altogether.
When I had a old beater I put whatever was cheapest/ convenient in it, as I didn't care. IN fact I would put all my old left over gas form the snow blower weed whacker chain saw etc. in it. Now I have to burn it, as my exploder finally did.
My opinion is you get what you pay for and I'm not gonna put suspect or unknown quality fuel in my high end/ high performance vehicles. If I wasn't tuned they be getting 89/91 octane.
My Charger and my Ram will always get brand name 93 octane.
The difference in price simply can't be a factor, If it is then your either way to cheap/ frugal or you have more truck than you can afford.
My vehicles don't technically NEED full synthetic either but they get it.
Not to say I don't use coupons or get my discounts, I certainly do.
I really think, without any evidence, that in the long run getting better than needed pays off.
Especially when I am towing an enclosed trailer with two big Harleys in it threw the mountains in 90 deg heat at 80 mph with the AC on and not a worry. A worry others might have it they ran around on 87 octane and then oh gee I better put some 889 init to tow...but I have half a tank...think it will be ok?