I always view Low as including three ish suits, the black one you wear to a funeral, the grey one you wore to every job interview you've had since you were 20, and the blue one you bought after you came into a little extra money and wore to your sister's wedding. None are tailored, they aren't expensive, but they fit well enough. Medium means you could wear the sort of suits that software designers in 90's movies wear every day to work, and you might have one or two nice suits - not the 10 000$ ones the bigwigs wear nice, but noticeably nicer then some wageslave's daily attire and they all fit well - maybe one of the real nice ones is tailored. High gets to assume you have a few of the latest and greatest coming from mortimer of london and Zoe in their closet, and update them every season (every 3-4 months, but this also assumes you only have one or two left from last season as you update, you don't get a stockpile). Luxury involves having hand-tailored clothes to your up-to-date measurements dropped off with your butler every month, and you can assume you have whatever your taste may be in the closet.
This is just based on my personal experience in the real world. The books leave lifestyle clothing vague, as far as I know, so salt to taste
There's a small section on page 217 of run faster about fashion by lifestyle. Don't want to go into too much detail but basically it say's . . .
Street/Squatter = Vendingwear which is recycled plastic with options on colour (avacado green or dirt brown) and size.
Low = Thrift store clothing, simple casual to business and knockoff brands.
Medium = Gives specific styles for business and fashion you can go up to around 500 yen max.
High = default to original tres chic clothing or go with the old world look ranging up to 1k.
Luxury = Designer clothing and can cost up to 5k.
So make of that what you will, you can live for a month at a moderate lifestyle off one of my dresses alone.