Haven't bought any for a while but Valley Vet lists it for $199 for 100ml and $495 for 250ml. I can usually buy locally a little cheaper than from valley, so it sounds like you are getting a good deal.
I like zactran. When zactran first came out, I did a little experiment with zactran and Excede for mass treatment when processing. Alternated 1 excede, 1 zactran for the entire group and had each calf marked by treatment. Had 1 less zactran treated calf get sick than excede treated but still very few for either. Due to less expense, continue to use excede for mass treatment. Haven't used any nuflor in a couple of years. For anything that gets sick after processing, have been rotating between draxxin, zactran, and zuprevo. Use the same one for about a month then change to the next. So far this has worked with 99% responding well to treatment. Started this due to hearing of folks using the same product for a long time beginning to have trouble with poor treatment response. Another thing I have learned is if I don't get a sick calf pulled early enough and it is already sick as a dog, it gets, in addition to a dose of 1 of the big 3, a 2cc/100 dose of baytril. Seems the baytril works faster and lets the longer term products finish the job.