Riding an electric motorbike does not answer the problem of pollution and global warming, of course. However, if you still want to get one, here are some tips.
Vo Thi Sau street is known to be the bike street. This is basically where you can buy mountain bike, regular bicycle, electric bicycle, and electric motorbike. The place you should go is The Gioi Xe Dien on 65-67 Vo Thi Sau street. They have electric bikes and motorbikes. For electric motorbikes, they have 2 brands: Dibao and Yadeo. Dibao will be cheaper, prices start at roughly 13,000,000 VND. The one displayed on the picture is Yadeo Umi, it costs 16,500,000 VND and you have different colours available. If you want to have the blue card, you will need to pay 1,800,000 VND extra, the shop will take care of the registration for you. Then, you will get the blue card 10 days after. Also, if you want them to produce/hang the number plate, you will have to pay 80,000 VND extra.
They say you can ride 80km but is more or less 50km. You will need 10 hours to fully recharge your battery.
The top case is good to install to avoid theft, it costs roughly 800,000 VND + workforce. The workforce really depends on how good you are at negotiation and where you go, can be 100,000 VND, but it should not be more than 300,000 VND.