Antique bowls are now very hard to come by and extremely valuable collectors items. Every other shop selling "antique" bowls is not really. Check your sources very carefully. 
 
Each antique bowl has its own story and history. It may or may not thus hold certain spiritual power.
 
The price of an antique bowl can range from $2000 - $10000 nowadays.
 
Inquire for what is available currently if interested.