There's really such case. My close friend brother got a Singaporean Lancer for RM 11k (by cash of coz). "Someone" will get you a valid roadtax and make the car driveable OTR here in Malaysia. Just road tax, the car don't have reg card and insurance policy. So avoid accident at all cost.
Regarding how to renew the road tax, you have to stay close to these ppl lo (like make friend or use runner). How much I really had no idea.