These are a great stand-in for the Billy bookcases, if you can't make it over to IKEA. They're not the sturdiest of shelves, but for the price, they can't be beat. I like that you can adjust the height on most of the individual shelves, making it customizable to what you need, and it comes with anchoring materials! 

The only thing that was tricky is that the boards are rather narrow in the back, so you need to be careful where you put your nails when hammering in the backing. But, I have these things loaded with books (heavy ones on the bottom), and I haven't seen any bowing or warping. Here's to hoping they'll last!