diff --git a/README.md b/README.md
index a97930c..a9677b8 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ value of the $USER environment variable as username.
         c4mate
     Find and buy item (interactive):
         c4mate <query>
-    Buy by item id (non-interactive):
+    Buy by item id (non-interactive, special id '0' will re-buy last item in log):
         c4mate -b|--buy <id>
     Show log:
         c4mate -l|--log [<size>]