Academy is cheaper.. I don't think there is a specific codestone you must buy when you're raising your pet so there is a chance of having to purchase a main codestone just to increase your pet's level.. In the academy, you can save quite a sum.. But as your pet gets higher in level and stats, you might wanna consider going to the training school cause' then training school will be cheaper.. That's my point of view..
You should really try the Academy. Dubloons are cheaper than codestones, that is, until you get to about level 50, then you should try the Training School. Also, (sometimes) on certain holidays, you can get your pets trained for free
I used to train at the training school as my pets had quite high stats, but since I've started again, I'm at the academy. I stock up on cheap dubloons with my ssw and then use them as I need them. Will have to change over to use the training school again soon though
i think i would first go to the academy till i reach the level 40, because the doublons are cheapes, then i would start using the codestones. but anyway the best way of training, (and cheaper for long time) is the lab ray, the problem is you also need good look lol