I checked and i don't think the generic for sporanox oral solution "Itraconazole" is available. ask the vet if this can be treated by Nystatin solution; that could save you money. best of luck
however, just an FYI the generic is the chemical equivalent of the brand name drug; there's no difference; that's why it has to be approved by the NDA and FDA
it's just cheaper because there's no patent on it and it's made and repackaged by several pharma companies; unlike the brand name which is owned and manufactured by only one pharma company.
Generic drugs vs brand name drugs on MedicineNet.com