workbook sheet protectors?

[Guest guest]

Has anyone ever come across any good techniques for protecting workbook sheets?

I use math workbooks to practice math skills with my child and it gets expensive to keep replacing the books. In the past I have slipped plastic sheet protectors over the page, use a dry-erase marker and reuse the page but it is often difficult to get the marks off of the plastic sheet cover. Are there any good worksheet or workbook protectors or other tricks out there? I need a side-loading protector since the pages are in the workbook and not loose pages. Thanks a bunch!