40 euros are, actually, more equivalent to almost 55 dollars, these days...
(But, I don't know at which prices are Kobo readers sold in North America.)
And, it's like Michał says...
The screens of e-book readers are horrible for any other use, other than to
read e-books.
If what you want is a Free Software-running tablet, there are some very cheap
tablets, that use the rather well supported Allwinner SOC technology
(http://linux-sunxi.org/), that are sold at those prices, and that can also
run Debian, already.
There was a French guy who was able to make two of the cheaper tablet models
run Debian on them - and, for one of those, he even talks about "native"
support for the touch screen and WiFi.
1) http://www.gregwar.com/old/?p=274
2) http://www.gregwar.com/old/?p=287 / http://www.gregwar.com/old/?p=324 /
http://www.gregwar.com/posts/debian-on-a-low-cost-tablet-50
I've even ordered one of these last mentioned ones, for myself, and am now
waiting to receive one, so that I can try it out, running only Free Software.
:)