There are netbooks available in the market. I own a Toshiba 10.1" and I use it to do simple tasks like Word Processing, Spreadsheet, Emailing, etc. Especially handy at airports, coffee-shops etc and not that expensive either. What is also good is that, in addition to using it for playing games, the kid can also learn stuff.
I am not against tablets. Only problem with them is that they are prohibitively expensive. Netbook would definitely have more processing power and memory than a normal tablet.
So, I would go for a netbook. Follow this link and it lists some netbooks under 200 pounds.