I think you should check those prices carefully, as one-way tickets are usually much more expensive, assuming you are booking with a major airline. Keep in mind that if you wait to book the return flight, until you are getting close to Santiago, you will need to pay whatever the price is at that time, and on shorter notice, so you really don't know what it will be. Are you moving into the high season or out of it?
It may make more sense to pay more for a flexible ticket that allows a change with just the fare difference, or even with a change fee. After all, you will be faced with that fare difference anyway! You must consider the following in your bet:
- How likely will your initial guess at timing (for your return) be wrong by enough to warrant a change?
- How much will the fares go up/down before you are ready to book the return?
- What is the current difference between a fare that doesn't allow changes, and one that does allow changes?
- How much is the change fee?
Keep in mind that some of the responses don't take into account that the fare conditions are quite different for travel from different parts of the world. The best strategy for travel from North America may be very different from the best strategy from Europe, Australia, or elsewhere.
Sometimes throwing away the return portion is the best solution in the end. But it is probably not the best bet in advance, if you think there is a good chance that you will in fact meet your schedule.
There way ticket inside Europe. so all is well for me. If outside of the good lands, tke your prece is no right answer!