No, there's no shopping in Paris.
JUST KIDDING. There are at least 20 streets that meet this description. You are not in the right budget for most of the Champs Elysée, but Les Halles area, Rue de Rivoli facing Tuileries (and its side streets), Blvd. Saint Germaine (and its many side streets), the Grand Boulevards with Printemps and Galeries Lafyette and the area around and include Bon Marché come to mind. These are the really obvious ones (like Oxford Street). There are lots and lots of others, and people will give you the names.
Rue Gabriel/Rue Montaigne area is as expensive as Champs, but they have their own ambience (but a 75€/$100 dress would be...unusual).
Indeed, for that price range, you are probably best off going to Les Halles and Rue de Rivoli between Bastille and Place Vendôme (a long stretch, btw) and if you are moved to do so, to investigate the side streets on the north side in that area.
Paris has lots of private shops/boutiques or small chains.
Unlike SoCal and Hawaii, there are not lots of T-shirt shops, so not sure what you're expecting.