Cleaning service is unheard of? I brought in my MTB to a nearby shop (Siglap) where they said they took apart the bike and cleaned the parts individually, as well as tune them after. About $120 total.

ok. I thought they also do some service on cleaning the bike chain and derailleur. Thanks for the advice bro.

I believe all bike shop offer tuning service. Cleaning service is unheard of. Please clean your bike before bringing to any bike shop to tune it. Also note that some bike shop only service the bike they sell. I would recommend bringing your folding bike to the shop you purchase from.