Certified GKH Gardening Expert
You can sometimes find them for sale at garden centers but there are several reputable online sellers that you can buy them from as well.
They are a pretty high maintenance plant and not as fun as people might think. They need very high humidity, so raising them in a closed jar or terrarium is best. They can actually die if you feed them too often as it takes an enormous amount of energy to close their traps.
You may want to look at a few other carnivorous plants, like sundews or pitcher plants. These will be able to eat far more bugs and are less maintenance intensive. Plus, several of their varieties don't need special containers, so you can enjoy them in the open instead of behind glass.