Bobby, a blue tounge lizard sounds like the kind of reptile your after. Having kept bluetounges myself for many years, i can tell you that with the right care, bluetounges can grow up to be a great pet reptile.
If you are able to, purchase a juvenile. By doing this, it allows the baby to become accustomed with being handled and is less likely to grow up wanting to take out a bite of you every time you handle it!
A cage 100cmLx45cmWx50cmH will be fine for a fully grown adult bluey. I use the recycled paper kitty litter as substrate due to it's ease for cleaning. Make sure a water bowl is present in the enclosure at all times and is always kept clean. At one end of the cage, provide a basking spot. I use a clip-on lamp with a 100 watt globe positioned onto a rock below and adjusted the lamp until i got a desired reading of approx 32-35 degrees C. If the enclosure is going to pe placed near a window, make sure to also provide shade and a shelter such as a log or hide cave.
I feed my adult bluey a varied diet consisting of banana, apple, dog food, snails, worms, crickets, grapes and pinkies ( baby mice, yes i know it might sound gross, but they love em). Feeding takes place in the enclosure on a dish every 2-3 days during summer and maybe only 1-2 times during colder months. Make sure any insects caught havn't come into contact with any insect killers ( baits).
A healthy bluetounge can be expected to grow to around 30cm ( head to tail). They are a great pet whose temperament and low maintanence make an ideal first reptile.
Hope this has been helpful