Figure $5-$10 per page. $5 would cover poems I can print out onto a single matching sheet of 8 1/2" x 11" paper, or plain paper embellished with stickers or simple cutouts. $10 would cover poems that require more complicated cutting and piecing, laser cuts/stickers I have to buy special, premium paper like metallic or handmade stuff, and 12" x 12" pages. Most poems could go either way, depending on how fancy a page you want. Some are an obvious match for easy-to-find paper (I can usually find leaf frames, flower frames, etc.) and others are just so exotic that I have to do a lot of piecing or stickering to make the presentation match the poem's content. Add postage for mailing in a cardboard envelope. After I've done this a few times, I'll have a good idea how much that will cost. Probably $1-2 since that's what most of my manuscript submissions cost.
If you're interested in buying a scrapbook page, contact me and we'll discuss details.