There's a welcoming school bus on this printable card, which can be used for any school occasion including "back to school". Print onto A4 paper - not card - and then fold twice.
Use this school frame in your scrapbook - there's useful space for journalling - or in the classroom. How about suggesting that older children write down what they would like to achieve in school this year?
Here's a simple "welcome back to school" card for teachers to print and give to their kids. It is designed to print onto A4 paper and be folded twice, so it is economical.