What do you call a person who is your friend only because you benefit them? [closed]

Solution 1:

hanger-on

a person who associates with another person or a group in a sycophantic manner or for the purpose of gaining some personal advantage.

Longman Dictionary defines it as

Someone who spends a lot of time with a rich or important person, because they hope to get some advantage for themselves: He was surrounded by a crowd of friends and hangers-on.

From Oxford Dictionaries

But he also set an undisputed world record, for the number of aides, acolytes, spongers and hangers-on that he assembled in one place at the same time.

Synonyms: follower, flunkey, toady, sycophant, parasite, leech; minion, lackey, acolyte; Informal: sponger, freeloader

Solution 2:

I think the term opportunist , though not specific to friendship, well describes the kind of person you are referring to:

• One who takes advantage of any opportunity to achieve an end, often with no regard for principles or consequences.(AHD)

also the expression fair-weather friend can suggest the idea of a person who uses friendship just as a way to to have a personal return without real commitment for others:

• Fig. someone who is your friend only when things are pleasant or going well for you. Bill stayed for lunch but he wouldn't help me with the yard work. He's just a fair-weather friend. A fair-weather friend isn't much help in an emergency. (AHD)