is there a ticket for one day or one week for subway and how much in Guangzhou

Hi, Guangzhou Yangchengtong Transport Card is suggested for you. If you just stay at Guangzhou for one day, no need to get a card. But if you will spend at Guangzhou for 7 days, it is a convenient way. You can get a card at the transportation office or some MTR station.
The card fee is 20 RMB and you need pay more to the card to pay for your transport fare.
When you finish using the card, you can also return the card and get the 20 RMB card fee.