In clothing there is a standard wholesale markup, which is 2.0-2.5 of manf costs, and a standard retail markup which is again 2.2-2.5 of wholesale cost. This means that they are selling it to the retailers at around 60 bucks or so, and then the retailer is selling it for 155. The 30 dollars provides money for rent, warehousing, salary etc for the brand/wholeseller. For the retailer it does the same. Retailers also sell in tranches (at 10-50% off) so they have a distribution curve through which they set price bins
$30 for the fabric, $30 for the store's overhead, $65 for the story that you can feel a part of every time it is on your skin.
Did you know my shirt was made in America and came in an Eco-friendly laundry bag? Oh don't worry darling, the Chinese peasant did a perfectly adequate job on stitching yours.