I am taking my wife and 2 sons (18,15) to Mexico in June. This will be our first trip to Mexico. Where is the best place to stay for the money?? I am not opposed to staying outside Cancun, ANY info is welcomed thank you!!!

My budget is around 3500$

I would head south of Cancun to the Riviera Maya area. There are MANY all inclusive resorts that are great for families.
Look into the Iberostar Paraiso, Barceló Maya, and Sandos Playacar resorts to get started.
All are family oriented all inclusive resorts with lots of activities.

Route 307 is the highway running south along the coast from Cancun. Every year a few new resorts pop up along this stretch, so there are now dozens of AI's between Cancun and Tulum. Some are on beautiful stretches of beach, some are on rocky stretches. We actually prefer non AI hotels, so I can't recommend anything, but a good resource to start research is locogringo.com.

We were looking at AI because we were worried about not speaking the language and safety in general- is this not an issue? Thanks!

You can easily stay in Playa del Carmen without AI. Not speaking Spanish shouldn't be an issue and the town is safe.
However.an AI resort will have LOTS of activities for your sons and other teens for them to socialize.

The entire resort strip from Cancun to Tulum is very safe, and 80% of the locals speak some English. This area is well touristed by Americans, Canadians, Brits, Italians, etc. We always chuckle when we talk to AI guests who are afraid to venture out of their gated resorts - they're missing out on half the fun.
Playa del Carmen is a good choice if you want a nice beach and plenty to do at night. Lots of mid priced beachfront accomodations. Akumal is the place for snorkeling, swimming, and quiet. Tulum is vast stretches of nearly empty beach and funky, eco-friendly cabanas and mini hotels. Puerto Morelos is a small fishing village/ beach town with some local flavor.

very safe. My family has stayed at the Cancun Marriott (JW) several times, and absolutely loved it. Not all inclusive, but wonderful quality.

My family and I enjoyed the Palace Resorts. We stayed at the Beach Palace and made day trips to Moon Palace and the resort on Isla Mujeres.