Most of the shops (such as Optical BB, Golden...) have the trials. Some common brands may fit other people but don't mean they fit you too. You have to take your time to find a fit one.
Such as me, I am using Cibx Vixion Focux Mosit. However, I have tried one-they acxvue but didn't fit as the curve of my eye-balls couldn't fit for this brand (Jackson & Jackson).