what is the market value of Ramilla Batra pottery?

The artist you're thinking of is called Romilla Batra,(with on O) and is of Indian origin. She has her studios in Berkeley, California.

Her work is ceramics, not pottery (a fine distinction to you and me, but a matter of different clay). Her style is sculptural and follows natural forms (opening flower-buds, eye-balls, eggs etc) and range from the tiny utility items like your little bowl, up to large sculptural installations.

Here's an exhibition review mentioning her work. (No illustrations, but I include it because the author is called Reena, LOL).

http://www.soumyasart.com/reviews/reena.html

I can't find direct price guides for her. At one exhibition of domestic items, that included her work, other artists' prices were around $250 for teaphots, to $500 for large vases, down to $25 for saki cups (tiny bowls for drinking Japanese saki).

I don't think you've discovered a $1 million masterpiece for 50c, but it most certainly would have cost 20 times more than you paid for it. The piece would be unique, in the sense of being totally hand-made,but maybe not "rare', as there would have been up to 20 similar ones on sale at the gallery where they were exhibited...the artists and gallery, after all, have to make a living, and they can't count on the one huge high-price item to be first to sell.

People can buy the smaller pieces as a souvenir of the show, and to have a tiny example of the artist's work at home to appreciate. It is now YOUR turn with this zig-zag sphere, which sounds lovely. Keep it where people can pick it up and admire it with their hands as well as their eyes.

(Narikomi is an old Japanese technique in which a piece is made up of layers of coloured clays. They are then carved away to reveal the different colours, to form the pattern (often a traditional scene). This is similar to how shell cameos are carved, and is also used in Japanese lacquer work. I once saw fantastic candles made by this method, too, the cut-away parts being left partially attached and curled into leaf and petal shapes).