Shops - Cape Verde
You can get eggs, potatoes, tomatoes, carrots, lettuce, cucumber, onions and other frozen vegetables such as peas, broccoli, cauliflower in most of the shops. On Sal they are mainly small shops, while on Santiago they have a few more larger stores and have much more choice and supply of fresh vegetables.
There are a few Deli's in Santa Maria on Sal Island where you can get some local bacon (like streaky) , meats, cheeses, fruit an d vegetables. There is one better mini market up in Espargos which has a better choice in frozen meats and vegetables. Street vendors will probaby try and sell tourists items at a higher price than in the shops, this happens on Sal anyway from my experience and with some friends. However if you know what the prices should be you can haggle. There can sometimes be a shortage of particular items on the island i.e. eggs/tomatoes etc.
There are also packets of pasta and noodles or tinned items you can buy. Good Back Bacon is quite expensive and not always available. Brits that visit their apartments on the islands on a regular basis tend to take in some of their favourite food stuffs for their own consumption, including sauces, bacon etc.
There are plans to open some slightly larger shops and stores on Sal, but items will continue to be imported. Most of the ships that bring in fresh produce arrive on the islands of Santiago or Sao Vicente to unload before being made available on the other islands.
Shops - Portugal
As it was an in-direct flight to Sal, I had some spare time to kill and took the opportunity to do a bit of shopping in Lisbon. I understood that the shops close on Saturday lunchtime for the weekend in the main area of Lisbon, but that the shopping complex is open on a Sunday daytime from about 10a.m. (but I would prefer you made your own checks on this, in case it changes).
I left my luggage and went off to Vasco Da Gamma, a large shopping complex in Lisbon so if you have time between flights you may be able to fit in a bit of shopping and doing the tourist bit, there is lots to see there. The shopping centre is only a short distance away and costs about 5 euros in a taxi.
Due to a missed connecting flight on another occasion, I was able to visit the shopping centre and purchase some 2 pin electrical items. I chose lightweight goods such as a kettle, toaster and an iron. They were much cheaper to buy than on Sal, plus you have more choice, some of the items I would post over at a later date, others I would take in my boxed luggage on the return journey.

