Where do you buy custord jello?

There is no such thing as "custord jello." It seems like you might be thinking of custard or Jell-O.

Custard is a creamy dessert made with eggs, milk, and sugar. You can buy ready-made custard in the refrigerated section of most grocery stores.

Jell-O is a brand of gelatin dessert that comes in various flavors. You can find Jell-O in the gelatin aisle of grocery stores.

If you're looking for a dessert that combines both custard and gelatin, you might be interested in a recipe for custard Jell-O. This recipe typically involves making a custard base and then adding gelatin to it to create a jiggly dessert.