1) Loremaster 2) Savage Paw 3) Samoori 4) Ninja Piglets
These suggestions are based primarily on the utility of the actual card, and balancing that against the number of Amber reagent you're going to need. The Ninja Piglets, for example, requires twice as much Amber as either Loremaster or Savage Paw, and yet the former two spells are way more useful.
The previous poster was incorrect about Savage Paw. Loremaster is a spell that places both a 20% weakness and a 35% fizzle on your opponent; Savage Paw places a 25% universal blade on yourself.