I think YesStyle probably buys their products from whoever their supplier is for items from Sechuna. If they sold their items for the same price, they'd make no profit. So, to make a profit they jack up the prices.
Personally, I prefer ordering from Sechuna itself because you can buy so much more. I was actually just in a group order for Sechuna. I'd reccommend you join one because basically, here's what you're paying for: your items, a service fee (normally a couple dollars), shipping of Sechuna to the person hosting the group order, shipping of that person to you.
Depending on how many people join and the location of the one hosting the group order, as well as how many boxes are needed, you may only have to pay around $8-$15 for shipping. (It seems like a lot, but it's very small compared to the overall $50 or $60 you would have to pay if you ordered by yourself). Then of course, the second shipping cost depends on a lot of things like how large your package is.