At this point, we should have our masterpiece edited by an editor, with a fancy cover waiting to be printed. Your carefully selected designer is ready to type set your edited text into a printable PDF file, with the cover at the beginning and end of the file. However, there is one more question that you need to answer.
What size do you want the book to be?
This practical question is very important to your wallet. Going with the US imposed standards, will cost a considerable amount more than going with the internationally upheld A standard. (i.e. A4, A5, A6 etc.) The UK has done a good job at publishing A-standard books, with A5 being the most common size for novels and novellas. If budget is tight, you should even consider A6 size, which at half the size will cost considerably less than A5.
A smaller book will also incur fewer shipping costs, which if you choose to swallow the cost or pass it on to the consumer, it will affect the final price of the product, which in turn, will affect the sales numbers. Then there is the question of, do you:
Print it in bulk or use print-on-demand services?
Bulk printing is the cheapest way (per book), but you take on all the risk. If your book does not sell, you won't get your money back. But using print-on-demand, means you will see very little, if any, of the sale money as profit. POD is the most expensive way to run a print, and this applies to everything from books to T-shirts. The costs are so high, you may even have to sell your book at triple the price you initially wanted to sell it at, just to cover the printing costs. But the great part about it is that you only pay to print books that are purchased already. This is a question only you and your budget can answer.
But, in typical Alice-down-the-rabbit-hole fashion, once you answer the previous question, another arises:
Who do you print your books with?
Printing is BIG business, and there is no shortage of entities willing to offer you this service. But from quality to price, speed and reliability, whom do you trust with your masterpiece? Had you chosen your Graphic Designer carefully, they should be able to help here. I need to stress the word SHOULD, and take their advice with a grain of salt. A print specialised designer SHOULD have connections with industrial printers.
Industrial printers are the ones who offer industrial prices, which will be cheaper than the commercial ones. But these guys do not offer their services to everybody. You see, just like design, printing is a much more complicated venture than what the masses would believe. There are a lot of invisible details, that if not properly addressed, will result in bad print-runs. Commercial printers have a legal obligation to refund money if the provided product is unsatisfactory. Industrial printers waver that obligation by passing on that responsibility to their customers. As such, they can only work with other businesses, who need to prove a background in the industry such as: publishing companies, design studios, event organisers etc. These businesses will be granted access to cheaper print-runs, in exchange for upholding all responsibilities over providing the artwork correctly for print. This way, the printers do not waste considerable amounts of time going backwards and forwards explaining to their customers technicalities such as bleed, flattening, CMYK codes etc.
They just print the file, without even looking at them most of the time. Are the colours printed wrong? Not their problem. Your designer, should also mark up these prices, in exchange for providing a guarantee of print quality. And depending on your designer, you may end up paying less or more than commercial rates. A bit more than your average commercial rates is a worthwhile cost for ensuring your books will print out correctly, but some of them may get overly greedy, so make sure to browse around, just to get an idea of what the going rate is. And another bit of advice, try and ignore the Google results with the word "Ad" in the top left corner of the listing. YOU are the one who is paying for the cost of that Advert.
Then what about ISBN numbers and barcodes?
Both of them are unique strings of numbers assigned to your printed work. They are used by retailers for administrative and tracking purposes. You are not required by any law to include these on your books, but many retailers will refuse to sell your book without those 2 codes. As with many things, buying ISBNs and Barcodes will be cheaper when bought in bulk. A good strategy is to buy them in bulk of 10 or more, for future titles. These can be printed on a sticker and applied to your covers after the fact. Or they can be included in the original cover print.
Also be aware of the "expiring barcodes scam". This is quite simply, where they sell you a cheap barcode, but then they expect you to pay a subscription fee every year, or they will expire it, making your printed novels worthless for retailers. Yes, it's a thing.
That's about it for printing. To sum up this article in one line: Measure 10 times, print it once. Research as much as you can, and get quotes from every printer willing to work with you before you take a decision. Do not let yourself fall victim to pushy sales people, and include your designer in this process.