Kobo offers e-book sales internationally, although I don't know if the selection will be good in Saudi Arabia, if available at all. They do geo-locate by IP address, which means that what you see in the Kobo store when browsing will be what you are able to buy, to avoid disappointments from looking at a title and finding out it is not available in your country when you login to purchase.
I think they charge in Canadian dollars internationally, so it may work out better for you to buy Kobo gift cards every so often to minimize currency exchange fees if you are able to shop from them.
Amazon officially says on their
international Kindle model page that they do not ship Kindles to or offer Kindle content to Saudi Arabia, unfortunately.
What international people tend to do is buy gift cards for the store they want to shop at and lie about their address (sometimes using a VPN IP proxy so the store's webserver thinks they are coming from the correct region).
Depending on what sorts of books you like to read, you may be able to find a fairly good selection offered by niche e-book stores which sell internationally or direct from the publisher. Generally, this works out best if you like romance, science fiction/fantasy, computer/technical books, and occasionally mysteries by either newer authors from specialty small press imprints or by older established authors now reprinting their rights-reverted backlist titles originally out from the big publishing houses themselves.
Hope this helps, and welcome to MobileRead!