Here is a cheap and easy prayer idea that struck me as I was looking at baking trays in the pound shop!
I had some magnetic tape in the cupboard and bought a pizza tray for £1. I wrote out some words to do with God and prayer and stuck a little piece of magnetic tape on the back of each. Now we have a 'magnetic poetry' prayer set that the children can use to make their own prayers! It introduces them to the vocabulary they can use in prayer and it also encourages them to express themselves. It might be worthwhile also to have some blank tiles so that children can add their own words to the collection!
Words I used include: God, Jesus, Holy Spirit, come, thank you, amen, light, amazing, love, joy peace, please, heal, help, world, power, pray, we, us. you, and, the, I, are, cry, know, heaven, praise, heart, to, for