Pokémon GO, the game that will be the closest thing we can get to being Ash Ketchum will more than likely have some microtransactions in it, but from the looks of it, it won't ruin the game.
Microtransactions have become a standard in most games, both in full retail games and in free online games, so the news about them coming to Pokémon GO wasn't really a surprise. From the looks of it, in the stage the game is in now, these microtransaction won't ruin the game or hide content behind pay-walls.
A new update to the beta version currently available in Japan and Australia brought a "Store" in which items such as boosts and upgrades that can be used in-game can be purchased. As of now no items like Ultra Balls, Potions, Antidote, and similar can be purchased from the in-app Store, only upgrades and boosts can be bought there.
Though all items inside the Store will be bought with PokeCoins which can either be collected in-game or bought with real money, for example, players get PokeCoins for logging in daily and those coins can be used to buy the upgrades in the Store without spending real money.
Another big update was a some changes and additions to the battling. A stamina bar has been added which forces players to mix up their attacks and not only use one type of attack. Players now have to mix between quick and charge attacks and stronger Pokémons can use the stronger charge attack more times in a row than weaker Pokémons, making the game more dynamic.
No release date has yet been confirmed, but a job listing suggests sometime during the summer. The job is for a short term marketing job from June to September and the listing points out that the position will only be needed "through launch", which would imply that Pokémon GO launches this summer.