A large oak bed flatpack can be made at a workbench (Oak workbench or better) in the workshop of a player-owned house. Like when making the normal Large oak bed, this requires 34 Construction, uses 5 oak planks, 2 bolts of cloth, and gives 330 experience. The flatpack can then be used on a bed hotspot in a Bedroom, either in building mode or not. This requires no Construction level and gives no experience.
The cost of making and selling a large oak bed flatpack from scratch gives a profit of: -4,780
After completing the hard Fremennik achievements, they can also be traded to Advisor Ghrim in exchange for 286 coins being added to your kingdom's coffers in Miscellania. See Flatpack: Selling to Miscellania for details.