Probably depends on where you live exactly. I'm originally from an extremely rural area of Nebraska, U.S., and the typical working class person there will be significantly different to even other parts of the U.S. I'll take a swing at it anyway:
Brands: Maybe Levi and Harley Davidson, but beyond that there's no brands that stick out to me.
Aesthetic: Jeans, denim shorts, athletic shorts, t-shirts (especially with the sleeves ripped off), hoodies, plaid button downs work shirts, maybe the occasional denim jacket or chore coat, cowboy boots, work boots, maybe tennis shoes, trucker cap, the occasional cowboy hat. One surprising thing might be accent - higher class people have more of a flat affect where working class is more "redneck" or "hick" for lack of a better word. This isn't completely one to one though, some working class people might have more of a flat affect, especially if they live in a bigger city.
I'm not sure about class markers except the accent thing. I think it'd probably be how big and new your truck is or how nice your house is. People don't really go for brand name clothes or luxury cars here afaik.
I think maybe there's been once or twice someone might've been surprised I was from a working class background. I dress pretty similarly to what I did growing up and drive a shitbox car so it most people probably aren't surprised.
No clue on accuracy of depictions of people around here. There is almost no popular media that depicts people from around these parts. If Nebraska ever comes up, it's mostly only jokes about how no one lives here. The closest thing I can think of is Superman's parents (from Kansas) in the Superman movie from last year - they were maybe somewhat accurate except they had southern accents for some reason.
