Yes, the Wind Breaker manga is over. It's been a wild ride from start to finish. You'll find that the ending leaves a lasting impression and gives a satisfying conclusion to the characters' journeys.
One option could be to check out dedicated manga platforms such as Comixology or Crunchyroll Manga. They often have a wide range of titles available, including Wind Breaker.
The cost of manga in Japan varies. You might find bargain bins with cheaper options, but collector's editions or limited releases can be quite costly. Also, it depends on where you buy them - big chain stores vs small indie shops.