Chaldea lunchtime

Pretty much get them from events and sell those 3 star exp cards.

The best MP farm method outside of event shops is to do the 40ap hands daily once and then spam the 30ap daily, selling everything you get.

Do the 20 AP Embers, and Burn them. Burn your silver servants you get from the gacha if you don't feel like leveling them.

Next event will allow you to buy 500 Mana Prism on the shop, also...