I use poly pellets. I got them from Michaels, they're expensive to buy here though. $8 for a bag and it did 1 8X8 bag. I overfilled a couple with the pellets though, I need to take some out.
Pony Bead, Small Silver Ball, Tassel, Feather, Eraser, Coloured Bead, Medium Bead, Toothpick,Clay Pot, Sequin, Coin, Glue Stick, Hand Button, Small Bead, Clasp, Ribbon, Coloured Pompom, Green Bingo Chip, Large Bead, Elastic, Charm, Soybean, Balloon, Bell, Felt Letter/Number, Plastic Car, Plastic Straw, Letter Tile/Bead, Plastic White X, Q-Tip, Popcorn Kernel, Playing Card,
Paper Tag, Peppercorn, Star Button, Googly Eye, Coloured String, Cotton Ball, Paperclip, Mirror
I would not glue the vinyl to the bag, it would be too easy to come undone and you'd have a huge mess.
You can buy a variety of thicknesses of vinyl at a fabric store or walmart. I bought the thickest I could, it is used to cover lawn furniture. I figure it's less likely to split or be poked open.