Reddit mentions of BCW-BBMAG - Magazine Size Backing Boards - White - (100 Boards)

I use these bags

And these boards

Because they're made for 8.5x11, they're a little larger than the magazines. Nintendo Power went through 2 major eras. Issues 1-90(ish) are taller than issues 91-285, so there's more white space in the packaged versions. The only other thing you need is some scotch tape. For a more professional look, I buy the clear tape rather than the cheaper, foggy counterpart.

EDIT: Forgot to mention, while the bags are a decent price on Amazon, a local comic book store has the boards for $9.99, so if you have any local mom and pop comic stores nearby, check those first. BCW is a good brand for these things.

I'll try!

This is the magazine boards. They work well and are nice and thick, but you might be able to find a cheaper alternative card stock.

BCW-BBMAG - Magazine Size Backing Boards - White - (100 Boards) https://www.amazon.com/dp/B002JQY0NG/ref=cm_sw_r_cp_apa_i_ql5UDbG47F7ZR

6 x 9 sleeves, I like these most

Wowfit 100 CT 6x9 inches Clear Cello Cellophane Plastic Bags, Re-Sealable Self-Sealing Cello Bags Great for 6x9 Print Photos A7 A8 A9 Cards Envelopes and More (6 x 9 inches) https://www.amazon.com/dp/B07VG7H175/ref=cm_sw_r_cp_apa_i_sn5UDbFR5EXJE

One pocket pages, these are a little frosty, not as crystal clear as I had hoped, but they work, and are cheap.

AmazonBasics Sheet Protector - Non-Glare, 100-Pack https://www.amazon.com/dp/B07R8DX3ZX/ref=cm_sw_r_cp_apa_i_so5UDb42A2C0T