Trundle for making quick-assemble mobile shopping bag

A mobile bag assembly comprising:

• a shopping sack of a disposable material having a bottom-end fold made such that when the sack is in a fully opened position, the sack is formed with a substantially planar base portion;
• a platform made of a synthetic resin polymer material and formed with at least two holes extending therethrough, the platform being configured to fit within the shopping sack and overlie the base portion when placed therein while the sack is in the fully opened position;
• and
• at least two wheel assemblies, each wheel assembly including an inverted U-shaped fork member having depending leg portions for rotatably mounting a wheel therebetween and a mounting assembly formed by two members extending upwardly from a central portion of the U-shaped member, the two members having enlarged portions at upper ends thereof extending outwardly in opposed directions therefrom and the two members being flexible for permitting flexing of the two members relative to the U-shaped member, wherein the mobile bag is assembled by placing the platform within the sack and against the base portion of the sack while in the fully opened position and inserting the mounting assembly of each wheel assembly into a bottom opening of a respective hole in the platform while also pressing a portion of the sack material into the hole, the mounting assembly being inserted into the hole until the enlarged portions on the upper ends of the two members are positioned above an upper surface of the platform and outwardly of a perimeter of the hole, thereby locking the wheel assembly to the platform.