These cubes are much smaller than they appear.  Only the biggest one is useful for shirts.  The next biggest one is good for a few pieces of underwear.  The other two aren't useful for any type of clothing, except maybe socks.  With this in mind, the cubes won't save you that much space.  What they will do is organize your clothing into separate pouches, and $20 seems like a lot to pay for something like that.  On the positive side, they're sturdy and the zippers appear to be well constructed, but again, I don't think they're worth $20.  If they sold a package of four of the biggest cubes, that might be something worth buying.