It is a Midas Chassidus [i.e. act of piety] for one not to accept presents, and rather to trust in Hashem that He will give one that which he lacks. [Seemingly, however, if this will lead to the person getting offended that his present was denied, or if the present is being given to help solidify a relationship, and strengthen the peace and love between two people, then he is to receive it. One can always offer to pay some money towards the present, and so was the practice of the Rebbe.]
Receiving charity: One who is need of charity and refuses to accept it, choosing to live a very minimalist lifestyle, is praised if he can support his basic needs without the charity. Such a person will not die until he becomes wealthy. If, however, one is in need of charity, and cannot make do without it, then he is required to receive the charity, and if he does not do so, he is responsible for his own suffering and is considered to have sinned.
Rav Gidal refuses to accept property from Rebbe Aba:
Rebbe refuses new car:
Rebbe pays for Megillah:
 Admur Hilchos Mechira 9 [same exact wording as Michaber brought next]; Michaber C.M. 249/5; Kiddushin 59a regarding story with Rav Gidal who refused to receive a present of property from Rav Aba; See Aruch Hashulchan 249/4 for why this ruling does not contradict the ruling of “Zachin Leadam Shelo Befanav”
 The reason: As the verse [Mishlei 15/27] states “Hasoneh Matanos Yichyeh.” [Admur ibid; Michaber ibid; Kiddushin ibid] One who accepts presents can lead him to chase after money and steal or become dishonest. Avoiding presents emphasizes one’s integrity. [Mefarshim on Mishlei ibid] Likewise, people are usually in search for money to feed themselves and their families, and on this the verse teaches that on the contrary, one who does not accept presents lives. The reason for this is because one who accepts presents is now “bribed” against chastising the giver for wrongdoing and he gets into the habit of flattering people. [Smeh 249/4; See also Shiyurei Bracha Y.D. 255 that Torah scholars who ask to be supported by the wealthy desecrate the Torah, and cause the wealthy to lose respect for Rabanim.]
 So can be learned from the Mitzvah of Mishloach Manos on Purim.
 Michaber 255/2; Rambam end of Matanos Aniyim; Last Mishneh in Peiah
 Kiddushin 59a
 See Hiskashrus 1025