although buying boots online without any input from a bootfitter isn't the best way to go... a good tip i can give you is to buy 2 sizes (your size and 1 whole size smaller). if you do find boots that fit online, i'm sure that everybody will tell you to go for the smaller size one since chances are that they will end up performing alot better for the long run but it will be important that you can feel the difference comparing both. i have a pair of dalbello rampages which where properly fitted and went for a whole size smaller (9.5 shoe size / 26.5 boot size) and i'm glad i did. so yeah do that and you'll probably end up maximizing your shipping costs.
do that and read this thread: http://www.newschoolers.com/web/forums/readthread/thread_id/311248/