Finding the right pay as you go CDN service (Content Delivery Network) with an afforable price, I would say an amazing price, is quite hard job. Lots of CDN providers try to offer a service, which has good quality, but the price is not balanced against standard traffic of WordPress sites. Even a price of 30 bucks per month is just too high.
Some providers brand their service as Pay as you go but in fact, there is a monthly fee again.
I thought I would end up with CDN77. I found out later that their pricing page is not at all honest. Some relevant information is missing, for example a 99 USD credit which you have to pay.
Anyway, this article is not a review of CDN providers; this is about a solution which has a simple name: keycdn.com
It is a Swiss-registered company headquartered in Winterthur. They have all you need. Enough data centres around the world. Features also for experienced users.
How much does it cost? One-time payment for credit is 25 USD. If your website doesn’t have very heavy traffic it is enough to keep you going for a long time.