Feints may be learned from the Death School, but all the cards above the feint have to be learned using your training points.
Bought with gold… you may find some at the Bazaar, price will vary due to how many Elik Silverfist, master merchant, has. Don’t rightly know if there is a level that has been applied prior to obtaining it as PVP’ers have to be level 20 before they can purchase the feint treasure card and death wizards can learn the spell at level 26.
You may also garden for the drops from the plants (GARDENING SOURCES: Deadly Fly Trap, Deadly Ninja Fig, Death Moon Seed, Evil Magma Peas, Fickle Pickle, King Parsley, Saw Palmetto, Stinkweed, and Ultra Huckleberries)
You can train Feint from Dworgyn in Nightside assuming you have the Training points and reach the appropriate level (26 I think). (Make sure to add the spell to your deck) There are also various item card versions.
TC Feint can only be purchased if someone sold it to the Bazaar. However, there are a few bosses that drop it as well. However, by far the easiest way to get TC Feints is to garden for them. Evil Magma Peas or King Parsley are good options to garden for it on as they have other uses as well.