I've run a classroom library for about 3 years -it can be rewarding if they start borrowing : ) Usually they need a good range of fun/interesting books, and lots of encouragement from the teacher. My grade have borrowed over 4,000 books since it started.
I've also ordered a few hundred books during that time.
It's best to start slowly and see which are popular, then expand (especially good if you can get them interested in a particular series or character -girls generally seem better at recommending texts to each other). Boys are harder. They like animals books, any super hero/star wars/lego based books -though you'd have to be careful of your school's feelings about those type of books. However I think if they enjoy it then it should be included to give them a chance for actual pleasure reading (though I try to have a lot of variety too).
It can be could to start with language controlled 'readers' as they're easier to read (less idiomatic speech etc), then add in some 'authentic' books later when you have a better idea of their levels.
I like these publishers -the levels I recommended should be accessible to most of your students. They also have some high interest 'character' books which the kids like:
"Step into reading" (levels 2-3, usually I get their character based books and a few historical figures)
"I can read" (levels 1-2, Rainbow Fairies, Pinkalicious,Fancy Nancy for the girls. Spiderman, Transformers etc for the guys!)
"DK readers" (level 1-2, non-fiction and star wars)
"National Geographic Readers" (levels 1-2, really great non-fiction)
"stone arch readers" (levels 2-3, Buzz Beaker was popular with the boys)
"first graphics" (these are stone arch's non-fiction comics)
"Graphic Library" (capstone press, these are more difficult comics)
"Nate the great" is a good early chapter book series, as is "Ricky Ricotta's Mighty Robot". Higher level is "the Magic Treehouse" "The Rainbow fairies" Chapter books, and "Geronimo Stilton". some other higher level fun comics are "Lunch lady" and "Babymouse"
I'd also highly recommend Mo Willems Elephant and Piggy series (very low level and really fun)
I usually order from "What the book" in Itaewon -if you're in Seoul you should have a look there. (depending on you order size it might be possible to negotiate a discount).
They also have a website:
http://whatthebook.com/(search the above titles on their site)
Also check out the rest of capstone's collection
http://www.capstonepub.com/They have some good hi-lo non-fiction for the older students
Here's the most popular Korean site for books if you want to comapre prices:
http://www.aladin.co.kr/home/welcome.aspxIf you like some more recommendations PM me : )