1998 Nissan Maxima Engine belt replacement

Hi - I am looking into buying a used Maxima 98 with 134k miles and 5 speed manual transmission. The person selling the car suggested that I might want to replace the engine belt (not the timing belt, since it has a timing chain) and he said that it would probably cost around $100. Does this estimate seem correct and how often should the engine belt be replaced on Nissans of this year? Anything else that I should really look into before buying the car? Thanks you so much!!!