We've coordinated several small weddings and many for just the couple. There are plenty of affordable options for an intimate beach wedding in Playa del Carmen. The trick is avoiding "packages" and doing it "a la carte".
The legal paperwork is not at all complicated, you just need to be here at least 3 days in advance with your passports and have your blood work done. A nurse is usually available to come to you. It's very quick. It does cost a little more than a non denominational ceremony though, and we do need to be sure a Justice of the Peace is available for you on your day.
There are many vendors to pick from and surely some in your budget for photography, flowers, etc.
Anything is possible!
Here are some of the elopements we have had the pleasure of planning: http://weddingsinpla...aya-del-carmen/