Hey Tommy, of all places, Museum Replicas makes well fitting, quality medieval shirts for around $40.00.  Most tailors will tell you to jump on that.  In addition, ebay has some good stuff, although it can be a gamble.    
            
            
            -Brother Knight Templar Sabatheous Tellinghast-
Knight Templar of the Order of the Brilliant Hammer
Holy Inquisitor of the Church of Kormyre
Crudelius est quam mori semper timere mortem
"Nothing is ever forgotten"
((Joe Bondi-Marketing Officer))