I guess my answer would depend on how adventurous you feel and how many groceries you are planning to buy.
The Vidanta location is pretty isolated in that it isn't walking distance to anywhere. If you're not renting a car, it's quite fun to experience the collectivo system. It's dirt cheap and is priced on how far you are traveling.
You walk out to the main highway and flag down the first passenger van you see going in the direction you want to travel. Ask them "Do you go near the Walmart in xx?" There is one in Cancun and one in Playa del Carmen.
If your Spanish is passable, so much easier for you, but even without any, people are very willing to help you get to where you want to go.
I actually prefer shopping at the Chedraui grocery store.
If you find yourself with too many grocery bags to walk back with, there are always cabs hanging around outside the stores. The cabs there are always cheaper than what the hotels will arrange for you.
Once you get used to the collectivo buses, you'll have a lot of fun with them. You can take them to Tulum or to any of the cenotes that lie along the highway.
The only thing to recognize in using them, that at around 5 pm all the hotel workers are trying to get home on them. Often times several will pass you by because there are no empty seats available.