I am looking at a house that I really like, but it has an in-ground pool. I would not use it and do not want the pain of maintaining it. If I bought this house, how would I go about having it removed? I assume that just filling it in is a bad idea.
I’ve actually seen a lot of people just fill it in. On the other hand, you could jackhammer the concrete decking around the edge (to about 18 inches down), demolish that, and remove it (trucking). Then backfill the actual pool itself, in essence burying a majority of it under the ground.
You’d have to check local codes on something like this, but my guess is that you may have to remove any and all of the structure (rebar and all). In which case, it ain’t a gonna be cheap.
Tripler
Personally, I’d do it with explosives, but then you gotta haul it out anyways. 
There are many ways to dela with it but seeing how a pool is a large investment and it adds value to the house if you ever want to sell it, I would try to find a solution which would not destroy it. maybe you can cover it with a deck or a structure which would be covered with soil but which can be removed if you ever sell the house. Or you could build a shelter against weapons of mass destruction.
I have heard of people filling them in. In one instance a tennis court was built on top. I assume that it would be like here, your local council would want to stick their nose in and presumably ther are building codes which dictate what needs doing. You may have to bash some wall down to get the sides of the pool below the new ground level and you would have to puncture the bottom so that it didn’t retain rain water.
Here is another idea. Look at the cautionary note at the bottom.
If you leave an in-ground pool empty for any significant period of time (1 year+) it will be damaged beyond repair. An empty pool tends to “float” out of the ground, depending on your groundwater conditions. Most pools have a hydrostatic relief valve in the main drain, which allows groundwater to flow into an empty pool to relieve this pressure and prevent damage. If you intend to keep it as a valued part of the property, you have to keep it filled, and that means maintaining the water, whether you use it or not.
My parents had one they just filled in with dirt and used as a flower bed.