The never ending alcohol problem

Hey y’all! I’m not the first nor will I be the last to say that alcohol for weddings is INSANELY EXPENSIVE. like downright crazy. We are having what I guess could be called a “cake and punch” reception but we will be doing brunch foods (YUM). As most will tell you about cake and punch receptions, they are usually held by people who can’t afford the whole Shabang fancy wedding (which is 100% my case). We recently got in touch with a caterer who can do everything but my cake and some donut holes (easy fix, whatever) they can also do mimosas. We were going to do a self serve mimosa bar but paying for someone to actually prepare the drinks and be staffed seems MUCH easier than setting everything up the day of. However this comes at a cost, they are $7/person with a flat $100 service fee-my Fiance thinks if we go this route we should pay by consumption making it never ending mimosas for our 40 guests. So the question begs, do I pay an exorbent amount to a caterer for the staffed mimosas or do I do a self serve station with just as much alcohol for cheaper? Anyone have any advice?