1

Flights between African countries in most cases never are cheap. I guess the cheapest would be to fly with TAP via Lisbon.

You can try the following: fly with LAN to Luanda, then with TAAG via Sao Tomé to Praia. You can google for their websites to get an idea on the costs.

2

Sorry, not LAN but LAM Linhas Aéreas de Moçambique

3

I´m not familiar with prices and connections from Maputo, but my general experience is that due to the relative small number on transcontinental flights you pay more to get from East to West Africa and vice versa than for a flight to Europe or even the US. There might be affordable connections to Angola, as both Mozambique and Angola are located at the Southern tip of the continent, and you will certainly get affordable connections to South Africa, maybe even with Kulua or other no frills (but good) airlines. Sao Tome and Cape Verde, on the other hand.... my bet would be on expensive flights

4

As I don't what do you mean by relatively inexpensive, I'll quote some of your flight options so you can look for fares and decide by yourself what do you think about them:

Regarding Cape Verde:

You can fly with TAP changing planes in Lisbon (either to Praia or Sal).
You can also fly with South African Airways (changing planes in Johannesburg) or with Ethiopìan (changing planes in Addis Abeba; you could need to stay overnight in Addis though) and with TACV (or maybe Senegal airlines too) to from Dakar to Praia.
LAM to Luanda and TAAG from Luanda to Praia can be another option but look carefully for the schedule and the visa requirements for Angola.

Regarding Guinea Bissau:

To fly with South African Airways (changing planes in Johannesburg) or with Ethiopian (changing planes in Addis Abeba) and continue overland is probably the best option. The alternative would be to fly with TAP changing planes in Lisbon.

Regarding Sao Tome:

You can go from Maputo to Libreville with South African Airways (changing planes in Johannesburg) or with Ethiopian (changing planes in Addis Abeba) and take a separate flight from Libreville to Sao Tome. You could need to stay overnight in the place where you change planes. Look for the visa requirements for Gabon.
Going to Luanda with LAM and from Luanda to Sao Tome with TAAG can be another option. However, LAM only flies from Maputo to Luanda is only twice a week and TAAG from Luanda to Sao Tome only once or twice a week too. Look carefully for the schedule. Look also for the visa requirements. If you need an Angolan visa, be aware they require a lot of paperwork. BTW, TAAG codeshares with LAM the flights from Maputo to Luanda.

5

great advice..thanks everyone