I've asked around on a few detachment forums to try and pin down what my first costumes should be. I'm down to 3 maybe 4 costumes those being ANH stormtrooper, shoretrooper captain, staff officer or maybe tie pilot (i don't think i found a screen accurate one yet).
For pricing from what I've been able to find (cheapest in price range)
Screen accurate ANH TK kit $350
Shore trooper kit $400 - $500
Staff uniform bought in pieces I'm going to go with $270 - $300 total
For fitting I'm 5'3 or 5'4 male the ANH kit would require A LOT of work to fit me, The staff uniform can be fitted pretty easily.
How well could the shoretrooper be trimmed down to fit? It looks like a lot less hard armor than the TK Mostly being torso and arms.