Go to Costco and get a camera lens kit by canon. Cheap option.

Thank you @Rarebear. I have a couple of good lenses (Canon 18–200 and Sigma 24–70) and a good camera. It is easy to buy things that aren’t all that useful though when you are learning.
I have a good tripod too. Polarising filters. I am thinking of a macro lens – because I want to do more close-up photography of insects/flowers, but not sure if that’s a good investment yet. So I thought it would be good to find out what the key things/lenses a budding photographer should have.

Oh and Costco aren’t in Brisbane yet. Probably won’t be long though. I think there is a store in Melbourne.

Get a good Canon 50mm f1.4 for low light with no flash shots and a 100mm f2.8 Macro. Should cost $900 to 1200.

@Bellatrix Sorry, I didn’t realize about your location. It looks like you’re set for cameras and lenses. I would recommend a polarizing filter. In term of a macro lens, they’re expensive.

I second @Tropical_Willie. 50mm lenses are sooooo useful and fun to use. Get a good one and you can do all kinds of stuff.

Thank you everyone. That was what was in my mind but it is so easy to go out and buy this lens and that and then you don’t use them very much. I don’t want to be ‘sold’ useless equipment that I probably don’t need by salesmen in a store. Thank you for your advice. And yes @Rarebear, they are but I do want to do more portraiture and I want to take better photos in my garden. So, (in time) I can see a 50mm lens would be a good option.

@Bellatrix When you get into lighting, check out http://strobist.blogspot.com/ – This is a great resource to save money and take some nice shots using strobes (external flashes)