If your toilet clogs fairly frequently, you need to investigate all the fixtures in your bathroom. Slow drainage in your sink could indicate that you have an obstruction in your main sewer line such as tree roots or sludgy build-up, and that’s going to require a bit more than a cheap plunger. But if the sink has no problem, the source of the clog is probably in your toilet trap. This could be caused by any number of things. If you have kids, don’t be surprised if toys, crayons, socks, toothbrushes or anything else is blocking the line. Or it may be that someone decided to flush facial tissue, paper towels or some product other than toilet paper down the commode. Those papers aren’t designed to disintegrate like TP. Or the problem could be that you simply have a poorly designed toilet and it just doesn’t work very well. In these instances a plunger can probably create a temporary solution. But if the clogs are frequent, you should probably have a plumber take a look. He can run an auger through the line to clear things up, or if necessary, replace your toilet altogether.