Join Dreamstime and there are tens of thousands of FREE to use images. If you want the fancy stuff there is a fee - either a monthly subscription, or purchase of a minimum of credits. A stunning image may cost 11 units. You must purchase a minimum of 110 units which costs £66.
There's a different platform that allows you to spend just the units required for a single purchase - I was convinced enough by some image that I paide £1.57 or some such.