docs: add tip

README.md

@@ -9,6 +9,9 @@ AI is becoming cheaper and more accessible, but larger context windows allow for
 - Tabularizing arrays of objects
 - Writing inline primitive arrays without spaces
 
+> [!TIP]
+> Wrap your JSON in `encode()` before sending it to LLMs and save ~2/3 of the token cost!
+
 ## Token Benchmarks
 
 <!-- automd:file src="./docs/benchmarks.md" -->