I wouldn't expect more than a couple hundred difference or so per fixture. If you need an extra fixture, go for it.

Regular pool lights are cheap,
I would say $300 to 350 more.
Also depends on the LED light, some are cheaper.

If he hasn't been installed yet, allow money for a possible 2nd niche and deck box to be installed. LED fixtures don't cast as many lumens as incandescent lamps.

Dont ask how much it will cost, ask how much it will save.
Most last 30,000 hours compared to less then 5,000 for standard lights. Use 20% of the electric of standard light.
And you get color, and mOOd lighting. You cant pay enough for mOOd lighting.

Of course if you live in a Northern state, you're looking at 150 nights/year at 4 hours per night or 600 hours per year. So you'll get 8+ years out of the standard light. Add enough $300 - $500 options and pool builds can get very expensive.

They quoted me $395 for the upgrade.

just-a-pb, good call on the number!

Remember what I said about the amount of light cast of an incandescent vs LED lamp.

How big is the pool?

One LED fixture may not be sufficient to properly illuminate evenly. If your adding light, do it right to prevent disappointment later.

the pool is 32 x 16 sorta kidney shaped with the light in the bend of the middleof the pool. Will one be enough?

Depending on your builder, expect a 350 to 450 upgrade to the LED pool lamp replacing an existing lamp.
If the pool only included a lamp and your adding a second you can expect 700 to 900, it'll depend on the length of the new lamp's electrical run to the switch, junction box, or the controller's power center.

quote" the pool is 32 x 16 sorta kidney shaped with the light in the bend of the middle of the pool. Will one be enough? "quote
IMO, no. If you placed it at one end aiming down the middle of the longest length you'd get just best return.
But it would look dim from outside the pool. When your inside the pool swimming it'll be fine.
If you want light from the side you described you'll need two. One on either side of the bend in the middle and no closer to each other than 10 feet in between the lights.

See ya,
Kelly

When you are placing two lights on the side of the pool (facing away from the house), I would recommend going with Pentair's IntelliBrite LED color lights. They have an ultra wide beam pattern that will look best. The other lights on the market have a much more narrow beam pattern so the corners of your pool may not be covered as well. Just my opinion from what I have seen.

A picture is worth ... you know.

{{!gwi}}
A little overkill but I have 6 colorlogics in pool, and 2 in spa.

beautiful