Matt - I think areas to areas are going to vary somewhat. Here is some of our info and background I am from the UK we have 36 holes and we have 27 buggies. In the Winter we only hire out 1 buggy per day, perhaps 2, most walk to keep warm. Our members are not big users of buggies but our day fee users are, rarely though would all 27 buggies go out at once, though occasionally I could use 50. I charge £20 per round say $32 and thats the going rate though some go up to 40. I have 15 good condition and a 12 that are a bit manky, I do a cheap members rate for £8 and I like to use those buggies. We also do an after 5PM rate for £8 for everyone and they get quite a bit of use in the summer.
We need the income from the buggies to keep staff in employment and I would say buggies to us are worth 2 greenstaff, so for the nay sayers against buggies, think before you type, when in this climate every penny counts. Whilst I tend to agree that walking is the game, the real world is "Can we book a buggy please, one of our party needs one?"..... "sorry sir, we dont have any buggies"......"In that case we cant play at your course" - a lost booking for 12 guys @ $100 each. Now I know thats a fact because I deal with bookings for other courses and as soon as you say a course has no buggies, that course is out of the reckoning regardless of any architectural merits and that situation happens once a week.
You make good money hiring out a cart, you make significantly less and take more off your client for a caddie, I dont see why you would do thios commercially.. I think your cart rental could go to $25 fairly easy.