BUT YOU ARE IN LUCK, because we found a bunch of similar or almost exact duplicates of Brandy Melville items from more widely available stores that do carry more than one size, many are less expensive as well, so enjoy!!
(These two skirts would probably feel pretty different though - Brandy's is a cotton-viscose blend and Garage's is 100% polyester)
Brandy Melville Jada Dress, $35 // Forever 21 Rosebud Dress, $17.80
Brandy Melville Bethan Dress, $29 // Urban Outfitters Sparkle & Fade Wrap-Back Skater Dress, $29.99
Brandy Melville Headdress Tank, not available // Love Culture Headdress Muscle Tee, $12.90
For basic skater skirts and crop tops, many stores like Garage and Forever 21 carry almost the exact duplicates but for cheaper. Feel free to comment with any of your own Brandy Melville lookalike finds!!