We did last year. We got the kit from polar pools. It ended up costing half of what it would have to have an installer do it.
However, we know a lot of helpful and talented people (one who has a backhoe and is an electrician). It was a lot of work and a stressful couple of months but it turned out beautifully. The kit was about $7000 or $8000 and the total cost was about $16,000. Is L-Shaped. Most of the cost aside from the kit was for concrete.
We absolutely love it and would never have been able to pay for one installed.
That is more than I expected a DIY pool to be. Do you have to concrete under the liner of the pool? My father-n-law can do the electrical work and my DH's cousin has a backhoe.
We have an inground pool also, and besides digging out a hole that large, there's also the complicated plumbing system, plus you have to reinforce the ground because water is so heavy, the electrics, the heating systems (we have 2 propane and solar), the ozoneator, etc etc.
Why not get an above ground pool? There's really nothing wrong with those.
Once you excavate, you install the walls, the plumbing and electric and then we (when I say we I mean DH and his friends) spread a concrete and vermiculite mix on the bottom before placing the liner in. We bought bags of both and rented a mixer to mix it ourselves.
We did hire a concrete truck to come deliver concrete to pour in behind the walls once they were up and under the steps. Then we hired a concrete guy to do the surrounding patio. This was the most expensive part.
The kits come with a video and the folks we bought from were very available by phone with questions. It is no small project, however. We could have done it cheper but we really wanted the l-shaped pool (rectangular was less) and we got a salt water system. We have quite a bit of patio around the outside too, which adds to the price. A pool of that size and shape would have been 35 grand to have someone else install.