Why would they have checked that at his regular appt a week ago when he only started showing signs yesterday?
Yes, those charges sound right. I've paid much more for antibiotics. You had an appt, where they did a UA and gave you antibiotics. You were charged accordingly.
It's not uncommon for puppies to get UTI's. You could get some D-mannose to put give to him daily.
~The strength of one's opinion should not exceed their knowledge on the matter~