It's a bag from shops that are more durable and you reuse them instead of using new ones each time. It's commonly called "A bag-for-life".
A bag for life is a durable plastic bag sold by some supermarkets in the UK for a small charge (typically 10p) which can be reused and then replaced free of charge when necessary. It is then recycled by the store.
Hovering over "am oes" gives "Is there a" as one of the possible translations. Can someone give an example of where am oes is used in that way?
Hmm, I "am oes" wouldn't be but "oes" would (Oes yna gastell ym Miwmares? Is there a castle in Beaumaris?), have you possibly misunderstood the prompt?