Some more...
A little girl at our church made homemade bread and sold it to raise money for her trip. She made it from scratch, literally...grinding the wheat herself, etc...delicious and healthy!
Her brother sold farm fresh eggs to pay for his trip (but that would require chickens which I'm assuming you most likely don't have)
My son's school group is presenting a Talent Show tonight. They each pre-sold tickets (100% of the proceeds from individual sales go into the individual's trip fund) and local grocers have donated sweet goods to be auctioned. The proceeds from the door and the auction will be divided amongst the students who are "working" working the event, i.e. setting up, cleaning up, bringing desserts, serving desserts to guests, etc.
Earlier in the year the same group of students held a "Soup and Silent Auction" event. They collected donated items for the auction and brought pots full of soup and sold tickets to the event. It was quite successful as well.
Of course, there are always Yard Sales and Bake Sales, and if they are legal where you live, raffles.