docs: added custom item price guide (#11240)

* added examples sidebar

* added guide

* fixes

* add meta image

* update intro

www/apps/resources/generated/files-map.mjs

@@ -783,6 +783,10 @@ export const filesMap = [
     "filePath": "/www/apps/resources/app/events-reference/page.mdx",
     "pathname": "/events-reference"
   },
+  {
+    "filePath": "/www/apps/resources/app/examples/guides/custom-item-price/page.mdx",
+    "pathname": "/examples/guides/custom-item-price"
+  },
   {
     "filePath": "/www/apps/resources/app/examples/page.mdx",
     "pathname": "/examples"