Are stamps collected in the past 20-30 years worth any money? My friend's grandfather wants to sell them but I figured it might be worth quite a bit. Is there any resell value now?

If rare or misprint.

you could check out ask for opinion. few collector shops located in penisula shopping centre (next to funan mall). use to visit them, now not sure whether they still operate there.

some hobbyists used to gather at basement of people's park centre in the weekends.​​​