One way ticket
 

I dont know if this is the right section for this question but whatever.

I'm trying to create a multi-city itinerary from KBL, going from there to japan then the west coast in the States. Then heading back to KBL, but why is my SFO to KBL(the last leg) more expensive than a round trip ticket from KBL to SFO. Can someone explain why??

ECO101, supply and demand

with the exception of low-cost carriers and/or short routes, one ways are almost always more expensive.

they're offered at the higher fare buckets with more flexibility, ostensibly because it meets business demands (or, rather, willingness to pay).

so yes - supply and demand

Also, flight pricing has nothing to do with distance flown.

So there's really no way to avoid this? Just buy a RT ticket for my last leg and just not fly the 2nd half?

You can do that, but if you no-show for any one flight on the itinerary, the airline will cancel the rest of it. So be sure you don't need that last leg, and you don't check any bags.

On a simple return that should not be a problem.

In some cases, it is cheaper to buy miles directly from an airline (when a sale is being run) and redeem for a one-way award ticket. KBL is served by Star Alliance members AI and TK, so if you can find a good sale on miles in a Star Alliance FFP that permits one-way awards at a good price in miles, that could be a good strategy -- if a frequent-flyer award seat is available on your desired date of travel.

How much is the roundtrip cash ticket?

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Its between $4100 and $4500 is the lowest ive seen for next month. I'm also talking about business class tickets.

I'd suggest checking united.com to see if a low-tier (United calls them "Saver") Business Class award seat is available for SFO-KBL on your preferred date(s) of travel. If a seat is available, then look for sales on United Mileage Plus miles, or Avianca LifeMiles. UA would charge 85,000 miles for such an award; Avianca would charge 78,000 miles.

If you can find the needed award seat and a good miles sale with either United or Avianca, you should be able to get the one-way award ticket for under $2,000.

But did you try pricing your entire journey as a multi-city ticket, rather than as a series of one-ways?

I remember the days of buying a ticket with an "Open Return." It was a RT ticket with no return date (likely within a year). Such an easy, effortless way to travel.

You can still do so obscure although technically it is not the same as you are referring to. I have bought return tickets with a return date a year out from departure and then just changed the return when I was ready to return. Either a changeable without or with change fee ticket will work just fine.