The price for next-gen games on the Xbox One will not be going up. Microsoft representatives confirmed first-party games on Xbox One will cost $59.99, the same price as most new releases for current-gen consoles are sold for. It's important to note that this only applies to first-party games, and that third-party titles could be sold for more depending on the publishers wishes.
At E3 last week, Microsoft also revealed a $499 starting price point for the Xbox One. And while the PS4 will be $100 cheaper at $399, Sony has still yet to reveal the cost for its own first-party titles. Back in February, Sony America CEO Jack Tretton suggested that games for the PS4 will "welcome free-to-play models, games from $0.99 up to those $60 games."
There's been some speculation leading up to the launch of PS4 and Xbox One that next-gen games could see an increase in price due to increased development costs.