Rest up by a stream

You walk through the woods a little more before coming across a small stream. Exhausted and sweaty from all the training for the day, you sit by it and relax, taking the occasional sip of water and a bit from some trail mix from your pack. It's quiet, with only the occasional rustle from the bushes by a cautious Poke'mon disturbing your rest. After a brief spell, you call out your team so they can enjoy some of the fresh water too. Pikachu and Bulbasaur immediately relaxed, and the Pidgey was soon to follow after it's initial shock. Mankey, however, remained stubborn, refusing to even look at your group. After about thirty minutes you finished resting.

"Okay, everyone, ready to go back into your pokeballs?" You ask, with generally positive responses, "Okay, lets get back out there and train!" You cry excitedly.

You recall the pokemon one by one, until only Mankey was left out. For some reason, you couldn't find his pokeball! Suddenly you remember a fact you learned watching nature documentaries on Pokemon journeys a long time ago. Something about how Gym Badges are one of the few ways to get higher level Poke'mon to obey a trainer. They recognized it as a sign of skill, or something. The fact was, however, you had no badges, and no idea how strong Mankey was.

You slowly turn, and sure enough, there he is with his own ball in his clutches.

"Man-Mankey! Mankey Man-key-key!" He seemed to be making some sort of demand of you. After watching for a bit and using a bit of intuition you determine he is asking for some reason he should travel with you. You're caught in a quandary, you are clearly to low level for him to respect as a trainer, but he will no doubt be necessary to beat Brock and avoid another gangbang. But what can you offer? Poke'mon don't need money or anything, so how can you get him to stay?