Tarantulas are often considered a low maintenance pet with many varieties available.  The more common species available in the pet trade are Mexican Red Knee, Mexican Painted Redleg, Mexican Fireleg, Curly Hair, Greenbottle Blue, Brazilian Black, Stripe Knee and Chilean Rose.  The one commonality among these species are their diets, all are insectivores and specifically cricket eaters although they will eat mealworms, superworms and Flightless Fruit Flies too.  A good rule of thumb is to offer insects that are half the spiders legspan or slightly smaller than the length their body.

Feeding a Tarantula everyday will allow it to grow very fast.  However, offering food every 4-7 days for young spiders and 7-10 days for larger spiders is a reasonable regimen.   Young spiders will keep eating until they are full, but this is not the case with adults.   Adults spiders may only eat onces a month, pay attention to their abdomen it should not be overly large or impede their ability to move.  Do not feed freshly molted spiders for up to two weeks.  Waxworms are intended to be used to add fat to a spiders diet and because they do not have bones like reptiles they do not require any calcium.  Although Tarantulas get water from their food it is still necessary to provide them with a small shallow dish full while in captivity.  

Staple Diet:
Crickets, Mealworms, Superworms, Hornworms and Flightless Fruit Flies

Supplement:
Waxworms (to add fat)