Cut and past from an older post I made in a similar situation, had one programmed key when buying my LJ. Summary, bought extra keys from the link below, now discontinued but perhaps still available somewhere. Paid for one key to be cut and programmed at a local dealership, had to call around as the charge for this varied wildly. Had the local Ace cut the blanks, I tested them in the ignition/door locks to make sure they worked, then programmed them using the two programmed keys I had after paying the dealer's ransom. Now I have 5 keys and should never need to go back to the dealer again.
"Had only one key with my 05 LJ - Had tried to go to Ace Hardware, who said they could cut/program the key, but after talking with them, they could not (for some reason they say they can do this again now??). The catch was, the key was somewhere on the order or $80 and if miscut or did not work, it was on me.
Got another chipped key from the dealer with programming for ~$150, cheapest of the few dealers around my area. Got the correct key cut and correctly programmed at the dealer and purchased three chipped keys from Car and Truck Remotes.com
Chrysler / Dodge / Jeep transponder key blank Y160-PT - Ilco brand
Talked the folks at Ace into cutting the keys for me and I programmed them following the directions from the Resources section here:
SKIS (SKIM) Sentry Key Programming Now have 5 total programmed keys in case I lose any and will still have enough (two) to program additional keys unless I really goof up!
Total cost ~$200 and some time, worth it in my opinion to keep the system in place and active."