If they're anything like mine, they lay all year long, but not in huge quantities. Eggs may also be infertile for awhile.
Egg and larvae care is basically all the same, but the thing with this specie is how small they start out and morph. Since they're so small its easiest for me to just leave the larvae in the parent tank feeding off micro inverts and leftover food.
Raising them can be tricky, they morph very small so feeding could be a little tougher. They also morph at a very small size, and when they morph they have the urge to go terrestrial which makes feeding even harder. Most people now a days try to raise them aquatic, giving them a very small amount of water and a lot of aquatic plants like java moss, and increase the water level every now and then.
They aren't for sale very often because of a few things, larvae take awhile to raise up and the fact that theres so many wild caught individuals that are easily available, so people won't pay a lot, and people I guess don't want to raise them up spending a lot of money to maybe get 5$ per newt.
In a few months Ive had 4 morph, and one of them didn't make it, the other 3 are still in a shallow aquatic setup. I leave all the eggs and larvae in the parent tank and take them out as the morph.