The Dutch international played with the Welshman at Tottenham and spent two years at Real Madrid, and he says that Bale's fee is not justified, though he wished him all the best.
Van der Vaart spent two years at Madrid as well, but he was in in and out of the starting XI, particularly in his final season, and believes Bale will have to adjust to the heightened expectations. The current Hamburg playmaker played alongside the Welshman for Tottenham between 2010-2012 but doesn't feel the pricetag reflects his ability.
"One hundred million euros is a bit much," van der Vaart told NOS. "You should ask yourself if a player is worth that amount at all. I've played with him, but I couldn't see that he was worth 100 million back then. He did develop quite good, but still he has to prove his worth at Real.
"I know Bale as a very nice and sweet guy so I think he would fit best in England. A club like Real Madrid is different and there is a lot of pressure over there. But maybe he can surprise everybody at Real."
Van der Vaart also believes Bale is below the level of Cristiano Ronaldo and Lionel Messi but added that he hopes the 24-year-old succeeds in the Spanish capital.
"You can't compare him with Messi and Ronaldo, because they're from another level," van der Vaart said. "If you make so many goals for so many years and win all these prizes they have won, it's not fair to compare anybody else with those guys.
"I've been in his situation, only Real paid a little less money for me back then. I would like to wish him all the best at Real Madrid, because Gareth is a great lad."