Not sure where you have been for the last...15 years or so.  
It shouldn't really be hard to discern that they are trying to scam you.  Nigeria is a no-brainer, so are many Philipinos, etc..  
Hint: never send money, especially overseas using money transfer services.  This alone pretty much makes you invulnerable to such scams.  You may only waste your time.
It's not just you, I get such solicitations all the time.  You think it's bad on a dating site?  Try a Sugar Daddy site.  
Then again, I kind of have the impression that something you do, say, or about you paints you as a target, considering the last couple of months.
And for kicks:  
http://www.419eater.com/