The problem with it if I remember correctly is that it has no fat. it's just cultured cow muscle peices ground together. so it's super lean ground meat.
The cost thing: they had to build an entire lab of specialist equiptment and hire biotech experts to culture hundreds of dishes of cells taken from a cow and grown in a culture medium taken from hundreds of cows for months... just to make one patty.
If you built a farm to raise a cow to make a single patty it wouldn't be a cheap burger either.
Once it's a continuous process where a single system can create multiple bugers and with minimal feedstock can continue to turn them out they'll drop in price fast. and eventually it could drop below regular meats in price.