Brenden, glad you like the pack. I ordered 2 yards of Xpac, one gray and one Kiwi and 1 yard of the 4mm foam mesh. Which was enough to make my first 2 bags, I had enough gray xpac left to make the bottom and back of my third bag. So you can get 2 to 3 bags with three yards of material. I want to say each bag cost like $25-$30 to make. You could save money by making a bag all the same color. As far as time spent, I took a lot of time thinking about what I wanted the pack to look like and what size i wanted the pack to be. I had all the fabric for a couple of weeks before I started cutting into it. Making those first cuts was the hardest part about making the bag. They only sewing experience I had before this was a not so cool sweatshirt I made in 7th grade Home EC.
I had no experience at all, I just took my time and made sure everything lined up and double and triple checked everything before I started sewing. So yes if you take your time and double check everything you will be able to do this project no problem.
So get sewing and show us some photos when you are done!