Bookish Discussion: Giveaways

Seriously, who doesn't love the sweet satisfaction of winning something? And generally speaking in the book blogging world, who doesn't love getting a free book (or multiple free books), swag, and sometimes free money to spend on books?!

Book bloggers find lots of reasons to host giveaways. If you participate in a book tour, usually the publisher provides some sort of giveaway either for individual blogs or tour wide. Bloggers who are celebrating accomplishments (like blogoversaries, reaching a certain number of followers, or meeting a goal) host giveaways. Bloggers who host events (like challenges and read-a-thons) usually include a giveaway too.

As a blogger who enters these giveaways pretty regularly and would love to host more, I've got lots of questions:

My thinking face...lol

Where do bloggers get the books (or funds) for giveaways? 

I know that when you participate in a tour the publisher/author usually provides a free book or swag for a giveaway. But lots of bloggers are giving away ARCs, boxes of books, and dollar amounts to various online book retailers. Are bloggers clearing out their shelves and giving away their personal book collections? Are bloggers paying for these giveaways out of their own pockets? If a publisher sends you an ARC in the mail, are you allowed to use that ARC for a giveaway? How many bloggers out there are using affiliate links to finance their giveaways? How do affiliate links really work anyways? 

How do you decide how long to keep a giveaway open for entries?

Again, I know if a publisher or tour host is running the giveaway, that they make this call. But for bloggers who are doing this on their own, how do you decide how long to keep a giveaway open?

Do you make any options for entry mandatory in order to unlock other options for entry and if so, why?

I assume bloggers like to host giveaways in order to increase traffic and followers, so does making certain options like "follow via bloglovin" mandatory actually accomplish that? or does it prevent non-followers from entering? 

On the flip side of that, do you allow entrants to repeat any entries daily? Does allowing entrants to tweet (or some other option) every day for multiple entries actually help increase traffic and followers?

How do you decide what to giveaway?

How do you decide how many entries to assign each possible thing a person can do to enter?

How do you pay for shipping? Again, I'm wondering if most bloggers are paying out of pocket or using profit from affiliate links for this or maybe some other unknown source?

Do you host multiple giveaways at one time? If so, how do you stay organized?

I think those are all of my questions, for now. I'm sure more will come up as the discussion ensues!

Please feel free to share your answers and any questions about giveaways that you have in the comments!