Looks like my Pix515e doesn'y have the option for DES or 3DES, do I have to buy a key or something from Cisco?
You do not need to purchase a license from Cisco. 3DES is now free and you can go to the software download on Cisco's website and register for the 3DES license. Once you fill out the form they will send you a license via Email. You then need to enter a few commands into the PIX along with the license and 3DES enables itself.