15 persons is quite a large van, I'm sure they exist but the standard size for rental is usually 11 people including driver. You might struggle to find a single van for rent of that size. On my page at: Cancun Car Rental 11 person vans are $121 per day via National with pick up and drop off at your hotel. Have you considered maybe taking a private tour to Xcaret instead of hiring a van? This would be just for your group, you pick the itinerary and times. See link below. Private Tours to Xcaret For $114 per person ($69 for kids) you could have private transportation (2 vans) and the Xcaret Plus package. The plus package would cost you $99 ($49.50 for kids) at the entrance if you were to drive yourself, so transport works out at $15 per person. For $15 pp extra you could also make a stop and see the ruins at Tulum. That's probably much cheaper than hiring a 15 seat van (or two smaller ones) and paying for gas. A lot less hassle too.