The pay is after Nigerian taxes, but you may have a tax liability in your home country. If you are a captain on any equipment, your pay will be $8000 in US dollars. But, only $7200 will be deposit by wire transfer to your bank account. The remainder will be paid in local currency (Naira) in cash. Pay day is the end of the month, typically paid a few days to a week after the fact.
The over night payment of N$10,000 ($70) is paid in cash prior to your trip on that day. You can buy a lot of beer for that.
The other payment is $1,000 US paid for recurrent training. Both captains and FO's do 6 month recurrent.
There's probably not a lot you'd want to spend money on here. You won't have a car, for instance. No shopping malls around here, or fast food, 24 hour stores, etc. Not many brand names you'd recognize.