Anonymous wrote:What kind? If it's a small, independently owned business the etiquette is to always be sure your purchase covers the time you spend taking up a seat. I wouldn't read in the store "for hours" unless I bought the book there as well as food and drink. I would also never spend more than 10-15 minutes with a book anywhere in the store unless I intended to buy it/had bought it (it's not a library).
But if we are talking about a Barnes and Noble with a Starbucks attached, I think that's different. I wouldn't treat it like a library but long browses are ok. I think most places expect you to buy at least a drink before you take up a seat in the cafe, but I wouldn't worry about how much I spent/how long I sat there. I would totally bring a book I bought elsewhere to the Barnes and Noble Starbucks.
Anonymous wrote:You can sit if there's a chair in the bookshop and read but you shouldn't go into the coffee shop to read unless you've bought the book in hand, really.