Barcelona is currently facing financial crisis, which has led them to explore alternative options. Because of their limited funds, they are offering multiple players in exchange for transfers. As of now, there is no negotiations between Barcelona and Mbappe. It's impossible task for Barcelona to get Mbappe under any circumstances.
Looks like this is just a rumor to heat up the situation. Indeed, there are many rumors regarding Mbappe, and it seems that this is what often makes his desire to go to Real madird fail. Regarding Barcelona, of course most clubs want to have the PSG superstar, but I'm not sure Barcelona is interested in making a bid, because it's true what you're talking about, this is again related to money. The news of Al Hilal's extraordinarily large bid for Mbappe is jaw-dropping. but at his current age, it was impossible for him to go to that league regardless of his salary. What he wants is Real Madrid, he has been for a long time.