I use whatever cheap plastic bowls (mixing bowl size) I can find at the dollar store. But I like things with rounded bottoms. Flat bottoms allow a few eggs to roll around as you walk back to the hous, and they whack into each other and crack. A rounded bottom leads to eggs that nestle together, do not roll and thus do not crack.
Cynthia's wicker baskets would also cut down on rolling because the bottom is slightly bumpy, and not dead flat. Of course if you have a steady hand and flat land between you and the house and your dog doesn't walk beside you leaping up and down like a lunatic, go ahead and go for a flat bottomed carrier.