postage

I can post the book - and indeed up to three of them - in a size 1 mail miser bubble jiffy. They count as large letters as they're less than 25mm deep (the envelope wont go any bigger than that)

1 book weighs 175g when packed - 70p 1st class, £1.40 first class recorded
3 books weigh 410g - 98p 1st class £1.68 recorded

The envelopes can be picked up for around 20p each (got my first 20 for 15p on special offer so I'm going back to the shop later to get another 100!)

I bought 1600 postage labels for 11.99 (another special offer from staples!)
even with the ink to print them that's only 2p a go.

that means that sending one book will cost £1.52 (print and delivery to me) +70p +20p +2p
a total cost of £2.44. Factor in a 15% return rate (pessimistic I know!) and I really need to recover £2.81 if I sell direct to make a profit. Potentially to drive sales I can sell a book delivered for £2.99!

However I have to remember marketing costs.