Non reving to South Africa help

So i'm trying to find the best route to go by as far as taxes go. It's kind of frustrating with our airline we have to email a pass request in with our credit card info and then they make the res for you and mail you the tickets. The problem is I don't have any clue how much they are going to charge they just make the res and whatever the price is they charge it without telling you. Does anyone here have any way of giving me a pretty good idea how much taxes would be non reving froming MCO-JNB-MCO. For right now my only options I have are with Lufthansa and Virgin atlantic as they are the only airlines we have agreements with that we can use that flies to South Africa...any info would be muchly appreciated