What exactly makes someone look “expensive”?

I’m not rich at all. In fact I’m the starving artist type but what I always feel good and take pride in is taking care of myself. Most of my clothes aren’t expensive either and I thrift very often, but I’ve spent a LOT of time reading about my body type and how to look decent in clothes without having to tailor so I’m careful about what looks good on my body and which trends to avoid. I get told that I look “expensive” which is very funny to me but hey I’ll take it. This makes me wonder, what exactly do people mean by someone “looking expensive”? My best guess is perhaps maintaining clear skin gives a halo effect but I just want to hear an opinion from others?