How much does it cost to feed the Blue Tongue Skink/lizard
$5 a week at most you can feed them a mix of canned dog food, pet meat, veggies you may have some they eat in your fridge like buk choy, carrots, pumpkin etc etc just google blue tongue food or something to many to list
How much do I have to spend on equipment. E.g, Lights
If you keep indoors you would probably be best to get a uv light.
A fitting and uv light would be your most expensive outlay at about $30 for a globe and $20 for a fitting and the globe would need to be replaced every 6 months
If you keep them outdoors with direct access to uv light (no plastic/glass blocking sun from entering you won't even need this.
Since you live in north Queensland i doubt you would need to worry about heating for a blue tongue
A tank can be as expensive or cheap as you like a decent sized tub around $50 you can get some decent sized ones from some sites or bunnnngs around 1000x500mm or 900x600mm/ a cheap cracked fish tank around 4ft plus you can pick up for <50 usually, or an expensive piece of reptile furniture for $200 plus normally
Are they cheap costing ?
Depends how you keep them and if you buy food just for them or have extra veggies around your house they can cost almost nothing, you don't need to spend heaps of money to keep reptiles healthy it all depends on how you want to set them up
Thanks.