Some teams have purchased a portable sound sytem for use while in Uganda which they then leave with a church or ministry team to use after they are gone. While I am not an expert in this area, I have found the
Peavey Solo® Portable Battery-Powered PA/Amplifier to be light, easy to pack and carry, and batteries are easy to get. Larger Photo
You will also need at least one microphone and cable such as the Pvi 100®. The unit has additional inputs for other equipment.