I can't say The Carpet People is really a good book. It's awkward, choppy, and overall feels like the work of an earnest novice, which it was. It also has quite a few very funny bits as Snibril and crew bumble around trying to escape Fray, snargs, and other evils.
The book is amusing on its own, but mostly of interest to Pratchett aficionados. The book contains both the original serial installments (crude but promising), written when Pratchett was quite young, and a substantially revised (more polished) novel version. The novel is much more interesting to read, but it's worth reading both to see not only the evolution of Pratchett's story, but the seeds of the later, more accomplished writer.
I got my copy for a couple of dollars, and that's what I recommend you spend. Interesting, somewhat funny, and worthwhile for historical insight, but not really a great book.