That's too bad #1 wasn't in there. VG+ copies of that go for ~ $50. New/NF $75 or higher. The first book is a must as it really sets up the series and characters. But each book is sort of its own contained story (with continuity between them), so it wouldn't be the end of the world to start with #2. Anyway, you might want to pick up a few of the early ones and see if you like it or not before buying the rest.
If you are curious to learn more about the author (Andrew J. Offutt), his son Chris wrote a great piece about his dad in the NY Times last year called "My Dad, the Pornographer". A great article, although it doesn't talk too much about the Spaceways series, unfortunately.
http://www.nytimes.com/2015/02/08/ma...pher.html?_r=0