In pursuit of sewing projects for my first granddaughter, I came across this one. No, the idea isn't mine and neither are the pattern and instructions. The actual website is here: http://www.straight-grain.com/?p=5142 and the pattern is printable.
By no means do I have mad skills at the sewing machine, so I was pleasantly surprised how easy it was to accomplish. My reason for adding this Instructable is to provide a few tips.
I made the inner bean bag from a vinyl tablecloth, which makes it waterproof for easier cleanup. ALL the fabric was purchased from thrift stores, from flannel sheets to baby blankets to table cloths to leftover fabric (AND the vinyl tablecloth) -- anything I could find that would allow me to stay away from the fabric stores, where it can become very expensive very quickly. The only items I had to buy were Velcro, a buckle, some fusible interfacing, and some more thread. It'll cost me a lot more to ship it to Hawaii, where my daughter's family lives, than to make the complete project.
NOTE: The second bean bag I made I bought a $2 vinyl tablecloth but it was too thin. Spent $4 at WalMart to get a heavier vinyl tablecloth. The tablecloths I used are lined in felt.
I sewed two covers, one with the strap-in as shown in the photo and another without the strap-in. This allows the bean bag to continue to be used when Baby outgrows the straps.
I filled it with polystyrene beads (http://www.walmart.com/ip/Ace-Bayou-Bean-Bag-Refil... The bag is huge. My suggestion is that you find a YouTube or Instructable to describe the easiest way to fill the inner bag. Wouldn't use the instructions shown in the link. I'm glad I used the tube method but still ended up with beads all over the place because I got careless.
Obviously, when printing a pattern to copy paper, it's not tissue paper and so it's a lot heavier and harder to pin to fabric. I've found that using Crayola's nontoxic water-soluble markers makes it easier and faster to trace the pattern directly onto the fabric. Any marks you make will then disappear in the washing machine. If I have to make two of one pattern, I trace the pattern on one side of the fabric, pin the two pieces of fabric together and then cut. Also, I used fusible interfacing in making the straps, the area where the straps will be placed, and also in the area the Velcro will be placed.
I hope you have as much fun making this project as I did!