Mbappe and Haaland are two of the hottest prospects in world football right now and they are expected to move clubs at the end of the season.
Barcelona have been linked with moves for both superstars although it remains to be seen whether they can even afford one of them due to their current financial position.
At the age of 23, Mbappe is already a world cup winner and he has scored 28 goals in 38 appearances across all competitions this season.
His contract with Paris Saint Germain expires at the end of this season, with Real Madrid his likeliest destination if he leaves France.
Haaland's season with Borussia Dortmund has been punctuated by injuries but he has still managed 23 goals in 25 appearances across all competitions this term.
The Norway international has a contract with Dortmund until the summer of 2024 but his €75m release clause will become active this summer.
Speaking to Sport, Alves said: "Mbappe is a more complete player than Haaland in all aspects of the game.
"I wouldn't do crazy things for Haaland. Honestly, I wouldn't spend a lot of money on him.
"I would spend a lot of money on Mbappe, but not on Haaland.
"If you are going to make a giant investment, you have to do it in the best way. If it depended on me, I would bet on Mbappe."
