In Thailand you have several manufacturers that sell Monkey bike style motorcycles. Probably the most popular one (at least in Bangkok) is the GPX Demon and GPX Country.
From Lifan motorcycles they sell the KPS150 (around 54,900 THB)
Stallions motorcycles sell the DAX, which is probably the closest you come to the original Honda Z50 Monkey bike for design. The Stallions Dax is powered by a 125cc engine. They also have the Momo Racer (around 38,800 THB)… and Stallions Motorcycles also have 3 more modern designs, the Solo Retro (around 49,500 THB) @1 (around 65,900 THB) and the VTR125.
If you looking for a Monkey bike style with a bit of an off-road twist in the design, then Lifan have the Pony and Zongshen Ryuka have the ZSR. The Lifan Pony (around 38,900 THB) comes with 100cc engine and the Zongshen ZSR (around 45,800 THB) comes with a 125cc.
I have been thinking about to buy an Monkey bike copy.I stay in Bung Khan is there anyone who have seen them been sold there?