I second fortytwo.sg. Otherwise carousell or q10 will be good too.
Ikea is aways a safe bet. Otherwise why don't you carousell it?
The ikea one seems not bad.. got both foam and spring options
Try Qoo, Kingkoil foldable bed is cheap and compact too.
Try fortytwo website.. they have cheap bed and mattress.
i got a steel bedframe fr qoo. and mattress at king koil
Ikea, carousell, or neighborhood furniture shops.
seahorse brand shop sells foldable mattress
Giant. I bought mine a sofa bed from giant.
Try those foldable king koil, Qoo?