Yes, Sandals regularly has sales for booking all-inclusive stays at their resorts.

Ongoing Sandals Sales
Some of the sales at Sandals are always available. First, there is an obvious hefty discount on “Rack Rates”, usually 55%.
Sandals Last Minute Deals
If you are looking to book a stay at Sandals Resort last minute, you can find deals that get your 4th night free. You can also combine these bookings with a nearby resort occasionally.
Sandals 7-7-7 Deals
The Sandals 7-7-7 deal is a discount of 7% off rack rate, that last for 7 days and is for 7 suites. Since it is off the rack rate, it ends up being 20-30% off the actual price so it is a reasonable discount. These discounts are launched each week until they are booked out.
Sandals Military & First Responder Discounts
If you are military or a first responder, you can get 10% off of your Sandals vacation.
Anniversary Night Sale
For Anniversaries, you receive your 7th night free during the month of your anniversary.
Occasional Sales at Sandals
Sandals regularly had additional promotions that can be found on their website.

Grand Opening Promotions
When Sandals opens a new resort, they always offer resort credits and discounts to incentivize travelers to give the resort a try.
Seasonal Sales
From time to time there are additional sales at Sandals. For example, earlier this year there was a Rhythm and Blues sale that included up to $500 in air credit plus a $150 spa credit on stays of 5 nights or more.