Living in Accra...two questions!

definitely too expensive to live on bottled water for the rest of your stay. I recommend standard water and everpure  as very good sachet water. hope you enjoy your stay. as for sunscreen, Accra Mall should definitely help.

I personally wouldn't use sachet water although I am sure there are some brands which are from a reliable source. When you boil a kettle why not boil more water than you need for a cup and then when the extra has cooled bottle it for drinking? Before we came we invested in a water filter and that has saved us money in the long run.

I've been in Ghana for nearly 3 years and I use sachet water only for cooking. I agree with hkann that it would be safe if you boil it for drinking.

As for sunscreen, yes, it is extraordinary hard to find in Ghana. I have recently bought one in the pharmacy in Marina Mall although I am not that familiar with the brand. Or else, you can try Koala, the pharmacy in Accra mall, and Game.

Hope it helps.