CreateSpace is Amazon's self-publishing company. It's fairly simple to use. You simply prepare your book in Word and design your cover as a pdf file. You then upload them to CreateSpace and choose the price you want to sell your book for. (The higher the price, the greater your royalties but, of course, high prices won't attract many buyers. You can also order 'authors' copies, where you buy your own book for a lower price but without receiving royalties but it's often simpler just to buy a few regularly-priced copes of your book. That's because 'authors' copies' are printed in the US and attract much higher postage charges than regular copies, which are printed in the EU, so they're usually not much cheaper really).
There's no charge for any of the basic CreateSpace services but there are paid-for services (such as cover design) available if you need them:
https://www.createspace.com/Products/Book/
(Click the tabs and links for lots more information)
Producing a Kindle edition is also fairly straightforward:
https://kdp.amazon.com/help?topicId=A17W8UM0MMSQX6