Prom, time for a reset?

[Duechristmas]

I have three daughters. The last is Year 11 and Prom is on our minds.
Dd1 had a modest event, and a high street evening dress.
Dd2 was a covid school leaver and so had no prom, which she wasn't bothered about.
Dd3 is being swept up in prom excitement, HOWEVER at her school it's a BIG DEAL. You are expected to buy a dress from one of the local outfitters which range from £250-800. Then there's hair, make up, nails, shoes, bag and transport. We are in a deprived area and the thought families are going into debt for this makes me feel sick, as does paying the price of a set of driving lessons for a dress to be worn for three hours.
We are now at an impasse. I want her to go, her friends and teachers want her to go, school hasn't been easy for her but she's almost there. However the prices and styles of dresses don't work for her. There's pressure that the shops close their orders by mid February.
She's a really sociable kid, she goes to parties most weekends, and yet this is causing stress and upset because she doesn't feel comfortable with the styles and expectations.
Any advice?

One of my dds wore a trouser suit to her prom. It's what she wanted. She was the only girl in trousers and she looked stunning. Slaters have a very good tailoring service and can adjust their standard male fitting suits to fit women. As girls grow much less than boys, dd will get many years' wear out of a suit that she loves. All my dc have ended up with items that they got more use out of after the prom, such as suits and shoes, so we weren't throwing money at a 3h event.

At all the proms my dcs have attended the outfits (in general, not necessarily my dcs') ranged from £££££s to high street to hired to charity shop. Ditto makeup and hair. Fuss was made and photographs taken of every arrival, regardless whether they arrived in a limo, a wheelbarrow or the family car.

Ignore perceived expectations. Help your dc find the outfit that pleases her, at the budget that works for you, not one that others may give a damn about.

DD has a Year 11 Prom this year and keeps talking about Prom dress shopping. I actually find the whole thing quite vulgar - she seems to think it's normal to spend £200 on dress. I feel bad but I'm simply not prepared to do that.

My advice is the same, whether you are mother of the bride, prom attendee or anything in between- wear something that you really like and a pair of DMs.

Vinted! Once worn, or never worn. Designer and branded rather than Chinese Shein type tatt. Much more ethical to buy from Vinted and likely much more unique.
A full length jumpsuit would also work.