When my first child was crawling around I had a basket full of different toys in every room. I also had one in the hallway. These basket of toys kept my little crawler out of trouble for some time. It kept him out of trouble until of course he found the kitchen cabinets and discovered drums (pots and pans). You can buy cheap baskets at the dollar store. Fill them up with different stimulating toys and let the exploring began.
Have fun 🙂