If you have a number stamped on the lock (most "lower priority locks" like inexpensive lock box locks, file cabinet locks for example will have one) you have two option that are reasonably quick and inexpensive. First, and quickest, is to drive the Jeep to your local lock smith. It's important, because he is going to want to know that the Jeep belongs to you, and you save the cost of having him come to you. He will be able to use the numbers to just cut you new key(s). If you don't take the Jeep, he will likely NOT cut you the key. You're other alternative is to call the manufacturer and give them the number and they will be able to provide you the key, but expect to wait a bit longer.