You can increase the PP of moves with PP up and PP max, but is there a maximum as to how much you can increase it? If yes, what is it?
It depends on the move your trying to boost base PP if the base is5 max is 8 if the base is10 max is 16 if the base is15 max is 24 if the base is20 max is 32 if the base is25 max is 40 if the base is30 max is 48 if the base is35 max is 56 if the base is40 max is 64
The maximum pp a move could have is 160% of its original pp.In other words 60% increase E.g Maximum pp a move such as fire blast with an original pp of 5 could have is 8
Sources: http://bulbapedia.bulbagarden.net/wiki/Power_points
There is a maximum amount you can increase a moves PP, but it is different for some moves. Example: Tackle and Electro Ball Tackle has a maximum PP of 56, while Electro Ball has a max PP of 16. Just find any move on the database and look at move data, next to PP it should say the move's PP and it's max PP in parentheses.