I picked up some "Super Saver" yarn from Walmart for about $2.50 (with tax) and was able to make about 3-1/2 projects with the one spool of yarn.
I don't know how to crochet very well, still just learning and currently only know how to do the single stitch and double stitch. The hook I used was G/6-4.25 MM.
I measured the length of a water bottle and double stitched the length and circumference of the bottle, then "weaved" the yarn through to create a seam. I left 3 single stitches at the bottom that I folded over the bottle when I had it in the partially finished bag and crocheted the bottom while the bottle was inside. For the strap, I did a row of single stitch then 1 double-stitch row and "weaved" the strap onto the bottle. When finished, I turned the project inside out, and you can't see the seem stitching/weaving.
I'm very proud of myself. This is the 3rd project I've done that has been completed and has a use, besides scarves! LOL