I like to preface that I work with schools through the auction process....I know very little about comapny fund raising....
Last year one of the schools I worked witht did theamed baskets for the classes: garden, leggo, barbie, painting, cooking, outdoor fun, sleepover boy, sllepover girl. spa, kid crafts, red white and blue, christmas, halloween........each child was asked to bring in an item that fit their class basket, we put them in metal tubs.
I also have worked with many schools with teacher/student stuff. Keep in mind that these can be huge in the money department. Theuy have a low retail value but a huge apeal for the kids and parents. we have done pizza and a movie, bowling, prom dress shopping, tea in Boston ant a swank hotel, overnight/girl night in Boston. mani/pedi party, treasure hunt for the little ones, canoeing on the river, rock climbing at an indoor rock gym. pool party, silly science, tide pooling...we have teachers donate time to help parents with digital photography, using the mac to help your child and painting a mural on a wall of your home. scrapbook a book with a theam. Sometimes people have a hobbie they would like to share.
All the schools I work with we use a buy it now on all silent auction. for gerneral stuff, GC, books, lamps, etc we use a %200 of retail value. The teacher fun stuff is a little more difficult to pick a number. it has to be a number that will not offend the parent group, a number you would be thrilled to get for an item and it has to be the same for all of the gifts.
One school I work with is in a very afluent community and have put as high as $2500 BIN, another school in a less afluent community would put a 200-500 BIN for the same item. You have to know your group, you have to play fair and you have to relize not everyone will win and that all teacher activities will not hold the same value because some teachers can be favored while others are less favored.