Definitely don't check an empty suitcase! It will be crushed and perhaps ruined by other luggage stacked on it in the luggage compartment of the plane.
Take a duffel bag or sports bag of some kind, fold it small, and pack it in your main suitcase.
When you come home, put only clothes and non-fragile items in the duffel, since it will give less protection than a rigid or reinforced suitcase. Put the souvenirs in the rigid suitcase.