In Bereshit 12:11-16, we see that Avraham was willing to receive gifts from Pharoah:
11 And it came to pass, when he was come near to enter into Egypt, that he said unto Sarai his wife: 'Behold now, I know that thou art a fair woman to look upon.
12 And it will come to pass, when the Egyptians shall see thee, that they will say: This is his wife; and they will kill me, but thee they will keep alive.
13 Say, I pray thee, thou art my sister; that it may be well with me for thy sake (They will give me gifts. - Rashi), and that my soul may live because of thee.'
14 And it came to pass, that, when Abram was come into Egypt, the Egyptians beheld the woman that she was very fair.
15 And the princes of Pharaoh saw her, and praised her to Pharaoh; and the woman was taken into Pharaoh's house.
16 And he dealt well with Abram for her sake; and he had sheep, and oxen, and he-asses, and men-servants, and maid-servants, and she-asses, and camels.
Yet he refused gifts from the King of Sodom (Bereshit 14:21-24):
21 And the king of Sodom said unto Abram: 'Give me the persons, and take the goods to thyself.'
22 And Abram said to the king of Sodom: 'I have lifted up my hand unto the LORD, God Most High, Maker of heaven and earth,
23 that I will not take a thread nor a shoe-latchet nor aught that is thine, lest thou shouldest say: I have made Abram rich;
24 save only that which the young men have eaten, and the portion of the men which went with me, Aner, Eshcol, and Mamre, let them take their portion.'
Rashi 14:23 explains why Avraham didn't want to take anything from the king of Sodom:
that you should not say, [I have made Abram rich]: The Holy One, blessed be He, promised to make me rich, as it is said (above 12:2): “and I will bless you, etc.”
Why wasn't he worried Pharaoh would say the same thing?