Geat top feeders are just gallon jars inverted either over the frames or over the inner cover. It doesn't cost alot of money to gather them up from a deli, or pizza parlor, or wherever they use them. You certainly don't need to spend 40 or 50 bucks each for them, unless your spending someone elses money.. then by all means.. get the ones the catalogues offer.
Bees just aren't that particular. They don't care if it is an old pickle jar, tomato sauce jar, or polystyrene feeder from mann lake. They want the syrup, however and wherever they can get it.