The title was worded badly because I'm pretty tired right now, but I thought it would be useful to put together an advice topic for people who plan on printing their own work and selling it.

So I'll start off:

Your running a business

You may only make a small amount of money off of the product your selling but its still a business, so you need to register your company (most likely you'll be a sole trader) and it needs to be declared on your tax return

That doesnt mean you'll pay tax on your companies earnings. Although it varies from country to country, to use the UK as an example, under UK law any earning under £6000 are not taxed.

If you are employed and earn over £6000 a year your job will of made up your tax requirement.

So why do it?

the main reason is legal protection, theres also the possibility that your company might grow.

product liability insurance

If your product arives at your customer damaged and causes injury to the customer or their property you are resposible for covering the damages.

Product liability insurance covers you against damages awarded as a result of damage to property or personal injury caused by your product.