Yes please help us @GoatMama !
DD here says don’t buy many clothes ahead of time. You’ll see when you get there what others wear, and you’ll know what to buy. She said in her school there isn’t a particular brand that’s prominent, it’s more a certain look that kids are after. Adidas, Bean boots, S Perry, and Hunter boots are popular for footwear. Girls wear lots of leggings, and lululemons abound. She said to bring lots of workout clothes because you’ll be in the gym more often than you realize. A few nice outfits for formal dinners/dances for boys. A few nice outfits for formal dinners for girls, and a couple of dresses for dances. You may want to wait buying these until you get a better sense of the school fashion. You can look at photos on FB, Instagram, and then school website to get a better idea. Also, girls borrow clothes from each other a lot. Definitely bring crazy, carnival wear like tutus, costumes, etc. for fun events.
As for winter jackets and parkas, kids at her school wear just about everything, from Columbia and North Face to Patagonia and Canada Goose. (Ha! No Canada Goose in this household…)
@CTMom21 - you have my children hidden at your house! They live in athletic pants and t-shirts (my '20 wears long sleeve ones in the winter with a hoodie, the '17 wears t-shirts all year long). S17 started wearing jeans in senior year.
@bc12345 - my son has survived in MA BS with mainly sneakers for 4 years. He has boots, but rarely wears them. I keep telling his grandparents he has appropriate clothing and it is up to him to make the choice of what to wear! He does wear a parka when it is cold - over his t-shirt.
@GoatMama your daughter is not at a formal dress school?
The problem is that my kids have been driven to school, door to door, for the past 10 years – no bus stop or walk to school. DS is in the short sleeves-and-hoodie (and sneakers in the snow) camp. Next year he will have to actually get outside and experience New England winter on a daily basis. I am fully on board with letting the dress code, peer pressure and some saintly dorm parents take over 
Nope, no formal dress. There is a dress code for the school day (8 to 3:30 pm) - no torn jeans, leggings without a skirt/long sweater, spaghetti straps without a cardigan over, T-shirt with prints, athletic wear, etc. - but it’s very basic.
Got it. The formal dress thing will be a little tougher to figure out - they have to show up with something that fits the dress code! We will certainly have eyes wide open on re-visit day.
I feel like this is the first time since he was 2 that I actually have a chance to buy things that are cute and preppy! I remember the day he told me he only liked silky (lacrosse) shorts. Broken heart! Haha. Last year at his LPS the principal made a rule that all boys had to be wearing a coat. It was wonderful.
To put #17 in a context, DD went to a small private school where no one would have blinked an eye if she showed up in her pajamas one morning. All she wore was T-shirts, shorts, and jeans. She left for BS with two suitcases, one of which contained exclusively T-shirts, shorts, and jeans. Fast-forward 6 months, and I have a nicely dressed girl wearing skirts, dresses, leggings, and colored jeans, and didn’t do a thing for it to happen! Add to that the fact that her old private school, where her younger brother attends, introduced a semi-formal dress code at the beginning of the school year, and I feel like an accomplished parent! 
@GoatMama, did your DD do lots of shopping online? How’d the wardrobe transition happen?
Yes, quite a bit of online shopping, but also lots of shopping during Parents Weekend in October; DD and I spent most of it in Boston stores. Then some additional shopping back home during Thanksgiving and Christmas breaks. Also, she goes out with friends quite often and they visit the local stores and outlet malls. Basically, she does most of her own shopping now.
My son has spent his first winter in the NE at boarding school and has told me that he does not need a coat because he is “immune to the cold”. He has two coats but refuses to wear them.
Did FA include a wardrobe allowance?
@CaliMex, not sure if you’re asking me… In our experience, no FA packages included wardrobe allowance, although the Hotchkiss scholarship included a monthly stipend. Her regional scholarship at SPS pays for everything but not for wardrobe.
(I was kidding @GoatMama, since it seems like one of those expenses one forgets to account for, especially for kids who aren’t used to dress codes or winter climes!)
Pro tip to pass on from my thrifty BS daughter - international students rarely want to ship all those clothes home at the end of the year! She was gifted many great hand me downs by her friends. (I think she borrowed most of her formal dresses as well which was a disappoint to me since I adore pretty dresses but I did manage to inflict my choice on her for her senior formal. Sorry/not sorry!) Also you can rent your books and/or buy used books, and the best deals are often on-line when it comes to text books.
^ :)) oh totally! An Uber. OMG Uber!!!
The kids at George School run a thrift shop on campus to keep all those outgrown clothes in circulation, to make shopping easy, and to benefit charity.