Some places do have a minimum number of hours that you must book them for, especially on a weekend or other day that is highly requested. I would shop around to see what the rates are for other companies in your area. Maybe also check the costs of a party bus instead of just limos? You may find a cheaper price elsewhere.
All of the places I've talked to have a 3 or 4 hour minimum. Try looking into other options if a limo isn't a must have. We're getting a limo Sprinter to get the bridal party to the venue, which was cheaper than a stretch limo. And for our getaway car, we're thinking of renting a luxury car from Enterprise for the night and getting one of our sober family or friends to drive us the 15 minutes to the hotel. When I priced it out, getting a Maserati for 24 hours is a little over half the price of a limo for 4 hours.
Yes it is normally. Unfortunately if you want a limo there’s no way around it. They have minimums they have to set otherwise they may be going to 4 different weddings in a day that would be very chaotic.