National Geographic for Kids is a brilliant magazine. I had subscriptions for my children and then take them into the classroom. The kids at school loved them too. You can buy the magazine as a one off at newsagents if you don’t want to commit to a subscription, or persuade a relative to give a subscription as a gift – it is exciting to get something in the post every month.
If the only thing your child wants to look at is a comic then that is okay. Once the interest begins you can broaden out but comics have stories that can be read with expression and shared. Allowing your child to choose a comic is fun but just watch that there is something inside not just an attractive gift on the front. For young children there is greater selection. I find the children between 6 years and teens harder (especially if they are a boy who is not mad about football). There are some ideas on this subscription site.
First News is a newspaper is aimed at 7-14 year olds and covers a huge range of up to the minute topics to interest children. You can subscribe online or buy individual issues from newsagents and supermarkets.