We discussed this in the Sun & Moon thread and thought might as well post it here. For the first few months of Sun & Moon's release you can get a Munchlax via Mystery Gift. It's Level 5, can have any Nature, has either Pick Up or Thick Fat, has a Classic Ribbon, and is in a Cherish Ball.
This Munchlax has been confirmed to know two event moves: Hold Back (a False Swipe clone) & Lucky Hour (a move that doubles the money earned in trainer battles). But there's more to this Munchlax then two exclusive moves, it's also holding a Z-Crystal: Snorlium Z. After evolving Munchlax into a Snorlax you can unleash a Z-Move only Snorlax can use (being this isn't the Sun & Moon thread I'll leave it at that).
The Snorlax Z-Move aside, Munchlax itself isn't that bad of an early game Pokemon, especially this one. In terms of being a battler it has a BST above the Starters which includes a huge HP stat and decent Attack and Special Defense. Defense and Special Attack isn't all that high but for early game they're perfectly serviceable. Of course its slow, and by that I mean its Speed stat is tied with Shuckle being the lowest of all Pokemon, at base 5. However as mentioned about it has the HP and defense to take hits and dish them out. Which is good as it means in trainer battles you can use Lucky Hour to double your winnings which should help with early money grinding. Also with Hold Back it would be very useful in capturing Pokemon. And as an Event Pokemon it'll earn double experience.
Also Munchlax evolves via Friendship so if you take good care of it you'll have a Snorlax sooner then you realize. Of course depending where you want to go with Snorlax you may want to hold off evolving Munchlax for a while:
Two notable moves Munchlax learns that Snorlax doesn't is Stockpile and Swallow. In Gen VII it learns these moves at level 28 and 33 (as of Gen VI). A bit of the way but if you use it often it'll have these moves by the time your Starter is about to fully evolve.
BUT if you go that route you give up some stuff only Snorlax can learn: Yawn (Level 20 as of Gen VI), Rest (28), Snore (28), and Sleep Talk (33).
So if they don't drastically change its level up moveset, its up to you: Do you want a Snorlax which can increase its defense stats & heal itself via losing those defense stats OR a Snorlax who can put opponents to sleep, heal & cure itself by falling asleep, & still attack while asleep.
Or you can get the best of both worlds by going the Stockpile & Swallow route and then use a Move Relearner to teach Snorlax those other moves you want it to have.