About hygiene or about the "only" part?
Because i said that half-jokingly. Expensive clothes don't make the fashion, Appropriate ones do.
Dress according to your age, bodytype, tastes and comfort (that includes location, for weather and company). Do it in the best fabrics you can afford; when choosing between two of same, the nicer material will always win.
A basic tee shirt can be fashionable if it makes you feel confident, make sure that what needs to be ironed is ironed, what needs to be tucked in is. And so on and so forth.
Lighter colors go on tops, darker bottoms. Spend some extra money on nice shoes and give them their intended use. Finicky materials are for special occasions because they will lose their appeal faster, that doesn't mean that workhorse garments will live forever.
Keep it clean, keep it neat and you're 85% there. The next 10% comes from your attitude. Brand only makes the remaining 5%.