Is the twin over full size good for two kids?

Yes. The twin upper suits a child and the full lower fits one or two smaller kids, or an adult. It is a common pick for siblings sharing a room.

What mattresses does it take?

A standard twin mattress on top and a standard full mattress below. Keep the top mattress thin enough that the guardrail still sits well above it.

How much storage does the side unit add?

The built-in side storage gives open shelf and cubby space along one side of the frame. It replaces a separate nightstand or bookcase in tight rooms.

Is $648.87 a good price?

Only one new price is listed, $648.87 at Lowe's as of November 7, 2026, so there is no recent range to compare. Judge it against other wood twin-over-full bunks with storage, which often run in the same range.

How hard is assembly?

Expect a few hours with two people. The wood frame and storage section have many parts, and building it in the room where it will stand saves moving it later.