Depending on your plane?
A friend recently took a C172 to Luanda.
FALA - FAUP - FYKT - FYWE - FYOA - FNLA
I know there was AVGAS in Luanda. He met the guys along the way (from Luderitz and from Luanda) to get fuel. If you talk to BP they can help if they know in advance? It is all depending on your range and budget? He paid R17/l in Keetmanshoop
VG300