Maybe, but I don't know how much I'll be ordering from them if I have to pay shipping on every single item. It costs a bit so it might work out cheaper to go elsewhere (though I love that you can track packages and the site itself). I'll have to see on a case by case basis.
I order a lot through Amazon marketplace and got used to being able to get a `fulfilled by Amazon` used book for £2 or so. Having to get a basket full of used books for £10 is a bit of a mathematical puzzle now !