Seo means "this" and sin "that", and both come AFTER the noun, which keeps its article: an leabhar seo is "this book". To ask a price, say Cé mhéad atá air? - literally "how much is on it".
Examples
- Cé mhéad atá ar an léine seo?
- How much is this shirt?
- Tógfaidh mé an ceann sin.
- I'll take that one.
- Cé mhéad atá ar na bróga?
- How much are the shoes?
The mistake to avoid
Seo and sin follow the noun and the article stays - an leabhar seo, never "seo leabhar".
Where this fits in
Food & ordering, Irish Gaelic A1: Order at a café or restaurant, ask for the bill, and talk about basic food and drink.