TBeyer … yes, you can print as many as you want.
There is usually a stipulation that it be for personal use. Some take that to mean "just yourself". Others take that to mean if you were playing a pirate game with buddies, one guy could print off all the ships for everyone.
But unless you buy a commercial license (most of the terrain I have backed don't have that as an option), then you are not supposed to print these "for sale".
However, if YOU bought the files yourself, you should be able to send that file to the person with the printer, and have them print it for you, and you reimburse them for their time and filament.
I suspect at this point in the development of 3D printers, you might have a tough time finding someone who will mess around with it for you, even if you supplied the files. People have issues with parts lifting from the print bed (so you reprint), or the spool runs out (so you reprint), or things are not level (so you reprint). Takes time, and filament. When it is something for yourself, it is easier to mess with that when you are accepting a fee from somebody else, and a clock is ticking.
I have backed many terrain projects, and some of these have yet to be printed. But I bought the files now, so that later I will have them. As printers get better and more reliable, something that was very fussy before might be easier to deal with 5 years from now. And I like to encourage people to offer up terrain files. So I back.