Sometimeish 'best' friend?

Basically me n my friend have known each other for like 6 years n instantly claimed each other best friends, but recently i cant help but feel like she takes advantage of me n what i have, its almost like she only calls when she has no one else to talk to or when she wants something, if i leave things at her house il see pictures of her wearing them n whenever she has other more interesting people round her she puts me to the back burner, n its like i don't exist, like she never invites me or involves me, n whenever were in a shop shes always short on money, so i have to put money to it, n whenever i need anything shes always broke, i just don't know what to say...