FSIL got married in Mexico at Karisma resorts in Cancun, all inclusive. I am getting married at Finest in Cancun next October, all-inclusive.
Highly recommend using DestinationWeddings.com. You'll get assigned a (free) agent who will pick you as many resorts as you want, based on your budget, timeframe, ceremony/reception desires, and more. My agent, Amy, made it seamless for me and for my guests!
If you do Mexico, it's cheaper September-Jan but November can be rainy. The beaches are still amazing during the winter months, so don't be deterred!
I chose Cancun because it was inexpensive (compared to other destinations) for my guests to fly to, the city is fun to party in, and it feels the most "safe" for people who don't leave the country often. i.e. versus Jamaica, Bahamas, etc.
We are getting married in Mexico! My fiancé is from there, and most of his side of the family still lives there (Cabo area). We chose April because it's not too hot by that point, but December is also a good time of year because usually hurricane season is over by then.
Most of the wedding venues you'll be able to find yourself are WAY overpriced and geared towards tourists. I was shocked that wedding packages in Mexico are the same or more expensive than those in Los Angeles. And the all-inclusive resorts we looked at mostly had options for weddings but not receptions...and they were mostly "beach" weddings which I do not want.
We got ourselves a local coordinator ( Paola at Cabo in Love ) and she is very affordable (she charges by guest count) and absolutely fantastic. Even better than other coordinators we interviewed who were three times as expensive. She helped us to find venues not listed on WeddingWire and not easily found online by ourselves, and some are SO cheap yet still very beautiful! We asked for a garden feel since I do not want a beach wedding. Here are the venues she showed us to choose from, with their approximate prices:
Baja Luna - $15k but comes with food, bar, and your basic rentals like tables and chairs.
Jardín Tropical - $2,200 for 50 persons (not sure if this goes up with more guests). This is the one we chose!! We are bringing in our own outside rentals and catering (taco bar and dessert trucks with churros, ice cream, and esquites)
Hacienda Oasis - $850 for the venue itself. $35 per person if you go with their menu (you can also bring in your own catering for no extra charge). $175 for each tables for 10 guests (comes WITH chairs) or again you can bring in your own rentals. This quote does not include bar/cocktail hour.
Our coordinator asked us for our preferences and style, and then sent us lists of vendors to choose from for Florals, DJ, Photographer, Live Music, Food, Rentals, etc. She's amazing at finding options within your budget and finding additional options if what she sends is not what you are looking for. She is also handling setting up hotel blocks near our event, with transportation to and from.