Please Help With May Wedding Bouquet

Our wedding is on May 24th, it`s hippy-ish with a celtic flair and we are on a tight budget. I can afford about $70-$80 total for my bouquet, my maid-of-honor`s bouquet, and a few bunches of flowers for an outdoor reception. My colors are Ivory, Sage, and Purple. I know I want a hand-tied bouquet, but I haven`t a clue as to what flowers to use....please help!! No preference to silk or fresh flowers...