There is a tiny grocers up the side lane by the chalet by the name of 'La Posette'. You can order a French stick there the day before and pick it up fresh the next morning. Our suggestion is that you stop at the supermarket by the name of 'Casino' in Bourg D'Oisans on your way to Venosc. It is very well equipped with all you need for your stay.
There is also a supermarket in Deux Alpes called the 'Sherpa' which is situated just near the Gondola station to go back down to Venosc. It is reasonably priced and is also well equipped.
Closest fuel station is in Bourg D'Oisans next to the Casino supermarket.
There are quite a few little boutiques, quality art/craft shops, honey shop and also an amazing dress boutique right in Venosc. Worth a look, there's something there for everyone!
Deux Alpes promises a great retail experience too, especially for 'fitness fashion'.