Pros
There was no interview: I just filled in a form and then brought it back to the shop and the Deputy Manager called me after few days, asking me to come to the shop for a chat. She simply asked me why do you want to volunteer with us? I said that I had a lot of free time, because I was looking for a job, and I wanted to do something more useful than staying at home all day waiting for e-mails. She said "Bored? I understand." So she offered me to volunteer there twice a week, on Saturday morning and Thursday afternoon (4 hours per shift). Later you can choose freely (but considering when there are few volunteers) which days and hours you want to work. Relaxed and friendly atmosphere, no pressure, you can always ask someone, they accept you even if your English is not very good. There is always someone else around if you have doubts or problems. Some volunteers are very nice and one gave me advice on how to find jobs or more exciting volunteer experiences. After maybe 4 times I got a chance to stay at the till and speak to customers. You can pick up a section you are interested in and you know something about (e.g. history books) and change items on display, decide what to keep etc. I asked the Manager if I could use him as a reference and he said yes.
Cons
Some volunteers aren't very talkative and often it's just sorting books in silence. The atmosphere isn't lively at all. A lot of books are thrown away even though they have only minor flaws (e.g yellowish pages): of course they cannot keep everything as they receive a lot of unsellable books or lots of copies of the same book. I don't always agree on how they set prices for donated items. One section I had ordered and repriced more reasonably (in which I am more expert than every other person there) has been changed after few days, separating books that should be sold together and raising prices for small books that are too old in their approach to the subject to have a good value.