If you're going that route then perhaps pocketbook or kobo would be a better option.
Mine was £94 here: https://www.argos.co.uk/product/4079659
Searching around for the pocketbook it's not sold in the UK but on their German store the cheapest model looks to be the 'Basic Lux 4 Ink Black' for €109 so seems the most price comparable.
The Kobo is more expensive though, the cheapest model is the Clara black & white edition and costs £129.99, at which point you may as well get a Kindle Paperwhite kids* as those are only £10 more.
*All kindle kids editions are the same as the non-kid versions, but come with a case, charger and extended warranty, there are no hardware or firmware differences.