If you're interested in a Shulk cosplay, as a semi-professional cosplayer, my advice would be make it yourself.
It's a lot of time and effort, but the feeling of satisfaction you get from doing it well and displaying the fruits of your labour is inestimable. The quality of a handmade cosplay is also potentially superior to a mass-produced product, which typically use the same material for every article of clothing and have little to no attention to the finer details. It's also a lot cheaper in the long run, as a store-bought cosplay can set you back anything from a hundred to a few hundred quid and isn't of the sturdiest fabric to begin with.
Of course, that's just my opinion. If you're gonna buy it anyway, you could always just commission a professional cosplay maker to do it for you. Most good cosplay makers will charge you about the same as a professional retailer and will tailor it bespoke to your particular needs and wants. It's also easier and more convenient in terms of shipping and handling, since they'll tell you exactly how long it'll take and when it's ready to be picked up.
When do you need to have this done by? How much of it have you already put together?