Why not give making your own stamps a go!
They can be a little tricky and you do need a bit of patience, but with practice (and I still need some practice) you can make anything you like…
You may also need, (along with patience) some:
cheap plain erasers (get different sizes, the bigger the easier)
some carving tools
some sharp and small hobby knives
Make sure to write/draw any words and pictures backwards, that is especially important if you want them to turn out the right way when stamped :-D.
Here are a few that I have made!
I love my little bird and bumblebee,
what do you think?