How about a dessert auction?
About once a year our youth pastor asks people to donate desserts for the auction. On a Sunday evening we all head to the kitchen area. He selects about 10 of the pies/cakes for the actual auction. The remaining items he places on table where people can pay a certain amount to purchase a dessert.
The auction items are big ticket items. $30 and UP!
The fixed prices are $5-$15.
We even do 3-4 cookies in a zip lock bag for $1.
This way everyone gets to participate. You may need to have a few "seeds" in the audience to help people understand the money is for the youth and you are really making a donation and no $75 for the apple pie wasn't too much. (you should give everyone who makes a purchase over $15 a donation slip.) These people may bid against each other to drive up a price. They only need to purchase a couple of items before everyone gets the idea.
One year we were keeping track of the donations and the amount was around $500. Some one in the audience asked if I would shave my beard if we raised over $1200. There were only 3 items left and I felt safe in saying yes. The last 3 pies all sold for over $250 each. I shaved my head, beard, and mustache on Saturday night. That Sunday morning at worship during children's time I did "children's time" wearing a ski mask. I told the kids that when they saw me they shouldn't laugh but that I should be a reminder to pray for the youth as they are going to camp. Then I took off the ski mask. My white head made a huge impression on the congregation. Every year they ask if I'm going to shave. Fortunately I can tell them "My wife says I can't shave anymore."

She also said that I, " looked like Herman Munster without the light bulb."
One part of the auction is children only. During that part of the auction only children my purchase an item.
It's interesting when someone purchases a pie for $50 and then cuts it apart to share with the rest of the group.
Ted Pate