Clogged Toilets
If your toilet clogs, you can normally clear the problem using a plunger. If you don't already have one, you can purchase one from most any hardware store or big box retailer.
Press the plunger over the drain hole and work it up and down to push the clog through the pipes.
Drain Issues
If your sink, bathtub, or shower clogs, you can also try to clear this with a plunger. Many hardware stores also sell drain cleaners you can snake into the drain to pull stubborn clogs out.