I landed in MPM from JNB yesterday.

The visa on arrival process is completely disorganised and seemingly void of any method.

Walking into the Immigration hall there's a more or less non-descript desk where two Immigration staff were working. Passengers simply approached in any fashion; there was no line much less directions on what to do. The landing (or actually an A5 photocopied piece of paper) wasn't available anywhere but from an Immigration staffer. So you had to first get someone's attention to get that. I filled it out and leaned on the desk facing a staffer for 25 minutes while she processed other passengers. Then out of the blue she looks at me and says "Where is your form?" As mentioned, there are no instructions about this form which, so helpfully, is only obtained from the desk draw of the Immigration desk!

All in all it took me 60 minutes. Unless you've got a lot of time and patience, I would recommend trying to get a visa in advance.

And here are the latest tourist visa fees: