Is it available to visit the store and trade in for MacBook in sg?
You can do it online: Apple Trade In - Apple
They'll send you a shipping box if that's available in SG.
Apple doesn't actually do trade-in estimates; they are handled by a service Apple contracts with.
Agree 100% with ku4hx: online is best.
The disclaimer at the bottom of the trade-in page ku4hx links has language suggesting not all stores have the same policies toward trade-ins. This:
Offer may not be available in all stores, and may vary between in-store and online trade-in. Some stores may have additional requirements
Frankly, based on my experience, doing a trade or a service in-store adds 1-2 days to the process. An Apple Store must ship your device to the same place you do. Ship-in eliminates this "middle-man" delay. Also you do not have to worry about scheduling an appointment if you ship.
Trade in
