l have several friends in the Philippines, and they usually expect my money. Is that a real friendship!?

Real friends don't expect money from you. Do not give cash to them.

No, it reminds me of the concept of how illegal immigrants in the US make up the highest GDP rates in Mexico because they send the money home.

These are not your friends tomodachi, they want okane for their lives. If you ever need anything they won't be around for you so please do not give anymore cash to them and walk away and find friends in different lands if this how you are treated. Love and honesty is friendship.

tell them that you don't have any money right now that u have financial problems, and see how they react. if they still  talk to you as always, then maybe the care about you. if thy do not talk to as much,  then maybe they just want your money. after 4 month if thy still talk to u as as always, like the same amount as when u was giving money then maybe thy care about you there is really no good way to know but this might give some idea 

The  women  sell  themselves  to the highest  bidder  to get  into the first  world  what does  that  say to you?

Would you still be 'friends' if you didn't give them money?

That will answer your question.

They are only your "friends" because you're sending them money.

It is their idea of friendship. 

Why  dont  you try NOT  giving  them  any money  and  see  how    your  "friendship"  lasts??

Use your head.                                                                                   .