There are two supermarkets in Tofo where you can get all of your non-perishables:
Yum Yum Supermarket & Mr Fresh Supermercado
Yum Yum is on the road between Inhambane and Tofo, after the petrol station on the way to Tofo. It is well stocked with a large range of products. We managed to get virtually everything there from meat, to oil, to milk, to sauces, cereal, fruit juice etc. They also have a range of vegetarian goods. If you are staying in Tofo, you will need a car to get there, or you can try and take a taxi. We went twice in 10 days to do big shops.
Mr Fresh Supermercado is in Tofo near the entrance to the village area. It is great for "top up" shopping and is within walking distance of most of the houses. They also stock ice.
The rest of the fresh produce and seafood can be bought in the market.