These goods are purchased with stolen credit cards.
Needless to say, those Money Orders or checks are no good, and not even worth the paper they're printed on.
If you cash them or deposit them into your account, Money Orders or checks will come back after few weeks as fraudulent and you will be responsible for paying back the money to the bank and sometimes even charged for passing counterfeit instrument.
Women are usually nurses, models, charity or UNICEF workers or antique dealers.
After they establish some lovely correspondence with you, fall in love and maybe even send a couple of cheap presents, they will either: a) be almost on their way to meet you, but something will happen to them: they will get robbed, beaten, get into the hospital, or other misfortune will happen and of course you will be their only contact to ask for financial help, or: b) tell you that their employer pays them with Money Orders or checks, and they can't cash them in Nigeria.