Madalas akong mag shop online. As long as the shop is legit by checking its reputation from other forumers or google searching its rep. Usually naman kapag big known shops even the local ones w/ good following is a sign na legit ang biz. My biggest concern is the siZing because it's considered as a blind buy for not actually fitting the products.... kung hindi local and the shop is abroad, pinakamaigi na makisuyo ka na lang sa kamaganak or kaibigan na nakatira doon. Or kung may forumer na nag offer ng proxy buying esp sa japan e it would also help but with a fee.
Pero kung walng choice, apart from the legitimacy ng online shop be wary about the shippong cost and duties/importation tax. Though some shops prepay the duties and taxes even shipping kasama rin w/c makes the shop attractive for the global market.