You should get some sort of reward every time you level up, similar to PGo. Lvl 2: 5 pokeballs + 1000 gold Lvl 3: 5 pokeballs + 1500 gold Lvl 4: 10 pokeballs + 1500 gold Lvl 5: Choose team + 2500 gold + 2 rare candies Lvl 6: 15 pokeballs + 2000 gold Lvl 7: 20 pokeballs + 2000 gold Lvl 8: 5 greatballs + 2500 gold Lvl 9: 5 greatballs + 2500 gold Lvl 10: 5000 gold + 5 rare candies + 1 lucky egg + 1 rare egg I feel like all players should be rewarded an egg at some point without paying, because 1, not everyone has the money to buy them, and 2, if players are thinking about buying an egg, they could get this free egg to see what opening them is all about, and then they'd be more likely to buy more. To add onto the whole egg thing, Level 20 would give an epic egg, and lvl 30 would give a shiny. Again, this relates to PGo because every 5/10 levels you get a few items only avalible through pokecoins.
I don't think this has been suggested before. It such a good idea. But what about the people that are already level 30?
I was thinking maybe a menu where you can claim previous level rewards for the people who already passed the level, if you are asking about the reward for level 30, probably a shiny egg a few rare candies a lot of money and maybe a lucky egg