I couldn't live without my Kindle and 3G
Kindle with wifi is £111 I think
Kindle with 3G is £152 I think. It's worth paying the extra £41 and getting 3G.
If you buy it at Tesco you'll get clubcard points, which effectively reduces the price.
There are loads of free books in the Kindle store which you'll come across if you hunt around. Also books for 46p, books for 86p, etc. (low prices) You don't have to spend a fortune.
A great thing about Kindle is that you can download a sample of your chosen book, which will be the first however many pages (5, 15, 30, 60) are included in the particular sample. The sample will give indications of whether the book is worth buying or not, and therefore save you buying crap books.
It's handy to be able to read all your books/newspapers at the same print size and in the same typeface.
Yes you should buy a Kindle. It will change your life. There are no downsides.