I had this same problem, my vet made me a whole bag (as in saline IV bag), and I was unable to use it before it expired. One thing to consider, offer to donate part to a local rescue group that accepts FELV or FIV cats (if you have any near you). It wont be any cheaper for you, but at least the "waste" would be going to a good cause. :-)
Phaewryn http://ucat.us/domesticcatlinks.html Special Needs Cat Resources
