This particular question is likely to create an internal struggle for anyone who is a book lover who wants to support authors and bookshops, whilst also considering the cost implications of perhaps doing so.
The original challenge stipulates that you have to pick one source where you buy the majority of your books, and for me this currently is online. However, I feel like I need to explain this a bit further.
I used to be a bookseller at Waterstones and at that time all of my books were bought from there. Not only did I get a really awesome discount on my regular impulse purchases, but I was always in the bookshop and therefore it was an extremely accessible source of new material.
Now that I have moved from the bookshop, I tend to find myself online a lot more. Payday comes around, and I will set up my list for the next month and purchase them all in a one-er and await delivery, not having to leave the comfort of my own house/office/whatever. For these kind of purchases, it very rarely is a result of browsing and moreso me ticking off my wishlist. I abhor browsing online and that truly is where bookshops excel.
Therefore, when I am in close vicinity to a bookshop or second hand shops, I will always make the effort to go in for a browse and purchase at least one new and unfamiliar title that manages to grab my attention. These particular purchases are the most exciting because usually they are unexpected and the impulsiveness of it all usually leaves me wanting to delve right in straight away!
So, in short, I buy my books from a variety of places. For those books which I know that I already want: online; and for those books where I want to discover something new: bookshops.
I haven’t really touched on the financial implications between the two, but it is well known you can get things far cheaper online. However, I think this is down to people’s personal finances and what they can afford. At the end of the day, I will promote anything that gets books in peoples hands.