I didn't nesssarily find that the skimmer increased my bioload, just kep my tank cleaner than without. Plus I have alot of corals.
If you are religious with your water changes, don't overstock or overfeed you should be ok without a skimmer in my opinion.
Otherwise, as stated there are quite a few hang on back models to choose from, ranging from cheapo to expensive. Give aquacave.com a lookisie, they have a great selection.