Cast iron pans are heavy, of course. They are made from iron, heated and poured into molds to cast the shape of your favorite dutch oven or skillet. If you care properly for your cast iron pans then you can expect many years of loyal performance.
First thing to know is that cast iron rusts. If it is left wet it will rust. Cleaning cast iron is easy, though. All you need is a soapy scratcher or "SOS Pad" to clean off even the most cantankerous rust. When it has been cleaned, rinse it well using very hot water. The hot water will help to heat up the iron, causing it to dry faster which will reduce the potential for rusting.
After the pan is washed well, dry with a lint-free cloth. A dish towel will work just fine. Put your cast iron pan on the stove and turn on the burner. The added heat will dry the pores of the pan. While the pan is on the lit burner, put some oil on a paper towel and brush the oil onto the surfaces of the skillet. This will season the surface and help to reduce rusting in the future.
There are those who will tell you to not use soap on your cast iron. This is not a necessary precaution. I have been washing cast iron cookware for 40 years and no amount of soap has ever spoiled the surface.
I do, however, recommend that you do not drop or throw your cast iron cookware. It is brittle and it can break on impact.