You will end up with 33 Slots naturally through leveling (can't remember which level). The total cap is 40. I can't remember the prices. Storage begins at 50g and caps at 150g. Farming evolution materials is luck based but you can go on hot streaks or dry streaks. They are tuned to drop once every 20-25 battles though according to a posts on FB from devs. One day I got 5 and then went 2 days and only got 1. I'd say let penny pester you about the evolving a monster. The Specials give the most experience to monsters so they are great for leveling. The experience a special gives is 800*it's level*it's passive. So a level 20 Special with 3 star passive will give 80000 XP. That is equal to about 80 level 5 commons. I'd use the red ones for leveling and try to find a Troop that does the first raid a lot. When you beat the 1st raid 6 times you get an SR Ice Dino. Then you can use the Brainfreeze to Evolve him.