Good thinking, Joanne. I actually lost money on my first two sales because I didn't think anyone would pay more for what I was offering. And when it comes to bookmarks, I did some research before I listed the one I made and I saw people selling a set of 4 bookmarks for 4 dollars. Even if they just print their designs on the paper and cut it, in my opinion that is still too little. When you consider the time it takes to design it, the paper, ink, etsy fee and paypal fee, you don't make any money if you charge $4 for a set of 4 bookmarks. So, I think your price is very reasonable, and I definitely think there will be people willing to pay for it. As for protection, I think laminating them would be fine.
Best of luck, I love your art.