That's great that you're looking ahead to plan for the start of the coming school year, making sure your child is prepared for 5th Grade. As a former teacher, I would recommend getting in touch with the school to find out what is appropriate for supplies. It typically varies from school to school, teacher to teacher and year to year.
Sometimes teachers send home notices to parents about supplies prior to the beginning of the year and sometimes they send one home during the first week back to school. If your child's school has a website, you might look there to see if a 5th grade student supply list is posted or get in touch with a student/students that you know will be in your child's class. I would hesitate going out to buy anything until you know what is recommended or acceptable and not waste money.
For home, I would recommend purchasing reference books, e.g., a college dictionary, a thesaurus and an atlas to compliment your child's learning. You can also find these tools online.
http://www.merriam-webster.com/ - dictionary & thesaurus
http://wordnet.princeton.edu/ - dictionary & thesaurus
http://www.google.com/Top/Reference/Maps/ - a list of atlas/map related sites
Hope this helps!
Best regards,
Lori