This hardcover children's book is a bargain at Readings. My kids have a copy and I've bought a second copy as a Christmas gift for my grade 4 girl's teacher. It says they have it in stock in store or delivery is $10. In which case you might want to combine it with some other purchases from the Book Bargains section to make it worthwhile:
https://www.readings.com.au/collection/great-bargain-books
Historium for $14.95 appeals to me as does Chronologica.
There's a new edition with 16 new countries apparently