Heading/Leading A Bake Sale

In my experience, having a "free will" offering, not set costs, yields the best profit.
And generally speaking the more hours goods are a available, the more you'll make.
Asking for an ingredient list is a little much, IMO.
People know what they can and can't eat.
Keeping nut items away from other items would be considerate.
Signs don't need to be specific. Bake Sale. Date & time. Location. Cause. Done.
In the past I've donated leftovers to both Meals on Wheels and a local mission.

Our school and ballet sometimes have by donation. This is not wise.

Occasionally they will get a big donor giving a $100, but that has happened twice in ten years. The rest of the time they occasionally see things go at less than the cost to bake.

I would also have water bottles for sale, possibly the mini ones if they are not allowed to take drinks into the auditorium. Also, they have a glass vase or pickle jar marked "Donations for X" so people can donate.

When priced, they usually do a baggie for $1.00 with 2 cookies, $5 per plate, and 6-10 per big item(pan of brownies, decorated cake, dozen cupcakes). They get $700-800 from 8-1 at Walmart or such on a Saturday. A preconcert sale would be about 30 minutes so I would open up afterwards in hopes of getting rid of the goods.

Our bake sales have always been a flat, $1 per item. MUCH easier to manage this way, and no one has ever complained. After all, it's for a good cause :)

I like the idea that everything be the same price. However I'd divide the items up so that the set price would be more for the more involved items such as mini-pies. $1 for a baggie of 3 cookies and $2 or 3 dollars for a mini-pie depending on how fancy the pie is. If you're having whole cakes they'd be more like $8-10 while a slice of cake could be $1 just like the cookies. Breads, perhaps $3.

So, all cookies would be one price, all mini-pies one price, all full cakes, pies one price. You could look at a bakery to help price items. If the foods are well made and attractive you could charge nearly the same as a grocery store bakery. Their prices are reasonable. McDonald's cookies are $.50 each.

I'd begin advertising the bake sale now. You don't need to list items and prices until the actual sale. Make large posters to post at the school. Send information home with students. My granddaughter's school has a weekly news letter that includes this sort of info. Too late to do that now but if you have to hold over the sale until the next week you could do that.

My daughter is gluten intolerant. I always buy gluten free items when they're available and labeled.

My local fire dept asks for donations for desserts, then charges for them. Since it's for a good cause, I think $2 for a slice of cherry pie is reasonable, $1 for a plate/bag of two cookies is reasonable. Often, I see that the cakes/cookies are very nice (Cheesecake Factory box) and probably cost more than they are charging for it! So, please don't undercharge. I would say 2 cookies is a reasonable amount to eat, and charging $1 for them is reasonable as well.

As far as a list of ingredients, perhaps you could label them "nut free" or "contains nuts!" depending on what you have fewer of. (maybe get bright neon stickers, like those at a garage sale, that you or the parent can stick on the baggie). I think people with a gluten allergy KNOW what they can or can't eat. So likely they skip over all the cookies anyway. Can they have rice krispy treats? Make sure someone makes those if so!

At the end of the event--have an UNANNOUNCED last minute dang near give away (cheap prices) of the leftovers.