泊めてくれたお礼。。。になるかは分からないけど
The character is offering his services as a thank you for being allowed to stay over. Why is "になるか" sued by itself here?
Is something being omitted? Maybe "I don't know if it will turn out good?"
He trails off in the first bubble 「泊めてくれたお礼…」 'To thank you for letting me stay...'
Then, with the sentence still connecting as he realizes this expression of gratitude may not be enough, he says 「になるかはわかんないけど」
「泊めてくれたお礼になるかはわかんないけど」 'I don't know if this [is enough] to thank you for letting me stay, but'
He was originally going to say somethin else but corrected himself mid-sentence