I sometimes use my index fingernail to flat pick the guitar. No plastic pick has that feel or gives the same sound. I have hundreds of plastic/nylon picks in my gig bag i purchased trying to find a familar feel and sound. IMO the tortoise shell flat pick feel and sound has not been duplicated using the many manmade materials. Many shell picks split early on but when you have used the same one for a few weeks it becomes part of you. The shell flat and thumb pick to the guitar is as traditional as the ivory pick is to the mandolin. The prices have gone up in the past few years to $20.00 for a flat pick and $50.00 for a thumb pick. The ivory picks can sometimes be made from old piano or accordian keys. The newer keyboards ivory is to thin. As Songbob says above you can make you own shell picks. Most of your first trys will split on first use but you will learn the shaping sanding and polishing tricks after a few trys. A walk in the woods will usually turn up the raw material. If you have a top of the line good qulity axe you really should experience the tortoice enhancement. Don't ask to borrow one....ever!