JO-anns doesn't carry hemp. technically it's not produced or sold in US. There are a few retailers online, but most charge WAY too much!
this one is about the cheapest place to get it without going through a co-op (a group of people that get together and buy a huge roll to get the wholesale price):
sewzanne's fabrics
Ebay is a great place also. I often see ads for 5 yards for $25. I think i figured out that you can get roughly 3-4 liners per yard. Since most hemp liners are at least $3, you end up saving by making your own.
5-6 layers of the hemp jersey is enough. Just make your liners the same size as your pocket, unless you want to make them bigger so that when your baby gets into larger sizes you can use the same ones.
just fold the fabric a few times until you get several layers, then cut out rectangles. I think a typical insert is about 14x5". this is much easier if you have a rotary cutter, but I don't, so I know you can still do it with scissors, you just don't get your lines as straight
You can also check the diaper swapper boards and ebay for inserts, you can often get them for less than retail. The only swapper board I go on is
diaper swappers. Just be careful that you know the retail price so you don't over pay.