i read a book in my childhood, that was possibly from a series. it was set in the future where the remnants of an ancient alien race had been found, scattered all over the universe. in particular, humans had found these alien ships that had these instant transportation abilities. the only problem was, we didn't really know how they worked. so you sort of pressed a button and were instantly transported to some point in the universe. it was seen as very risky, because you might transport to someplace really far away and never be able to return. but there was also the possibility of transporting to a place where lots of alien artifacts could be found, so you could return and become very rich.
that's sort of all i remember. i've thought about the books a lot over the years, but just could not remember who the author was or what the book(s) were called.
thanks for your help! : )