I personally will never spend money on food to skill up. As far as GS goes, I've skilled up on the mandragora in Altep. Just by killing a few they can get to be Even Match fairly quick. That and the fact that WAR can use the multi-hit GS on Auction House, though it costs like 1.5 mil now, it has a low damage so you can do more swings against one mandragora. Just sub DNC and stack on the Regen atmas. And if you have any Physical damage down gear, that helps. With the multi-hit as well as a WAR's Double Attack, you wont even need haste.