There are different versions of the COVID 19 vaccine and there is a large variation in their price. And in most of the developing nations (as well as some of the developed nations), the government will pickup the price tag and the citizens don't need to pay anything. Two of the most effective vaccines are costly, with the Moderna vaccine costing around $75 for two doses and the one from Pfizer costing around $40. The one from Sinovac (China) also costs around $60 for two doses. The Sputnik V vaccine of Russia is a bit cheaper, with a price tag of $18-$20 for two doses. These vaccines have an efficiency of around 95%.
But most of the developing nations will prefer less effective vaccines, which are cheaper and easier to transport. The one from Oxford-AstraZeneca costs only around $8 for two doses and it has an efficiency of around 60%-70%.