Modern History book suggestion

Hello!  I am rounding up resources for the upcoming year and have a question for those that have been through Modern with their 9th graders.  I’m having trouble finding the book “World War I: From the Lusitania to Versailles” for less than $30-$35, either new, used, or borrowed.  :/  We are on a bit of a budget, and have three other children, so I’m having a hard time justifying the expense for one book (even though he is the eldest and theoretically, this book will be used for several years/children).  How vital was this book to your experience?  Is there a comparable substitute?  I’ve never even laid eyes on the book, so I don’t even know what I might be looking for in a reasonable substitute.  Thanks for any information you can give!