This is nearly identical in scope and sequence to many Longman editions.
CK-12 provides customizable, interactive “flexbooks” that you can export as PDFs. Their Grade 8 material is robust and aligned with Common Core (similar to Longman). longman mathematics grade 8 pdf
Many schools purchase site licenses for digital textbooks. Check with your child’s teacher or school librarian. They may already have a portal (e.g., Pearson Realize) where a PDF version is available to students for free with a login. This is nearly identical in scope and sequence