Cellulitis, high fever, hr and bp. went to er. hospitalized, vancomycin, i&d, go home w/bactrim. could this case have been handled in a cheaper way?

Not really: Only possibility would have been earlier detection either by you or by doc-- then oral antibiotics plus or minus i and d could have prevented hospitalization and need for IV antibiotics.

Probably not: You were treated appropriately. If you had sought medical help earlier you might have been able to have been treated with out- patient IV or oral antibiotics and avoided costly hospitalization.