Not ON the beach, but one vendor a day will be set up next to the beach in case you would like to do a little shopping. They also brought in several vendors the night of the beach party who set up around the Main Pool.
Most days there is a man on his surfboard with conch shells out by the rope and 1-3 vendors up off the beach by water sports/towels. One day last August they filled the garden lawn with a wide variety of vendors to share the Jamaican culture with guests. I don't know if that was a special event or weekly. All of the vendors we interacted with were friendly and while they are good salespeople they were never aggressive. Their goods were also better than what we found on the shopping tour and more authentic (paintings, pottery, spices, jewelry, wood carvings etc). If you're seeking generic souvenirs which say "Jamaica" then the shopping tour will offer the opportunity to find those. Personally, I much prefer the handmade items.
Both answers are correct "conch Man" is out on his surfboard every day out past the ropes and they have a vendor set up by the new nightclub for some small items, no pressure at all. and of course the vendors by the pool at the beach party. We will be back August 23-31.
There are different vendors on resort every day close to the beach. They're all very nice and will barter. I do a majority of my shopping through them rather then going in to town. There is also multiple vendors on site for the beach party night.