A collapsible support structure includes a horizontal support structure, a vertical support structure, a handle assembly, and an axle assembly. In use, the collapsible support structure may be folded/unfolded between a deployed configuration, in which the collapsible support structure may be capable of rolling along a support surface to transport items, and a stowed/storage position, in which the collapsible support structure is collapsed in a compact geometry for storage. The collapsible support structure includes an axle assembly that enables removal of the wheels from the axle assembly for storage, as well as a handle assembly that can slide completely underneath the horizontal support structure for storage and when not in use.