Vueling is offering good prices for flights to some Western African countries like Senegal and Gambia.
Validity: December 2016
Travel dates: 2017
1) Barcelona – Dakar EUR341 11-18.03.2017
2) Barcelona – Banjul EUR331 22-29.04.2017
For accommodation I recommend you to search hotels for Dakar and Banjul on HotelsCombined as it aggregates all booking portals including Booking. You can find hotel reviews on Tripadvisor which is also great for searching best places to visit.
Hostelworld offers perfect budget accommodation for students, backpackers and low cost travelers.
If you want to stay with a local, you should rent a room, apartment or house on Airbnb. When you travel on Airbnb, you will get €18 in travel credit as my referral.
I suggest to rent a car from RentalCars if you want to drive around these incredible destinations.