We suggest to buy mosquito spray in your home country.
Only in a few supermarkets in Accra you can get good quality spray.
Most Mosquito sprays you get in Ghana don't have enough "Deet" inside so they won't protect you from tropical mosquitos. The Ministry of foreign affairs of your home country informs about recommend sprays against tropical mosquitos.
Please notice that in most cases the need of mosquito spray is underestimated!