where do you live? if you want to try before you buy, then you will need a shop that sells tri kit - and bearing in mind that between brands they can come up slightly different sizes and different fits then it's always best to try and then decide which is best.
I've had Pearl Izumi and 2XU shorts over the years - the 2XU is my preference. I bought a new pair last w/e and tried Orca and Fusion shorts but the 2XU's still felt the best fit or me
you can buy online from loads of places but that can be a faff if they don't fit and you need to send them back for an alternative.
Edited: 29/08/2012 at 17:05