melbourne it 
i have just been sent a email saying my domain address needs renewing soon for my website!
Thought perhaps £10 to £20
Click on it $180 us dollars for 2 years!
Has to be a joke surely?
Domain name renewal is usually pretty cheap (maybe a tenner or less for two years. Is the higher figure for services other than just the renewal? $180 for two years is quite achievable if you have bought webspace/potential bandwidth with it and possibly email boxes.
Check other companies' rates. It may pay you to renew through another company and let them transfer it in - though there may not be much saving if you are using additional services.
123-reg is quite a user friendly host for such things. It's UK based too (assuming you're in UK) so no currency conversion charge.
Alternatively, maybe you can reduce the bandwidth needed to run the site and pay less? Compressing images with some simple software could help you use less. Do you pay for a lot more bandwidth than you are ever likely to need? Maybe reduce the package? Be careful of this as some hosts charge you more for the portion of bandwidth that hasn't been pre-paid (effectively a small fine) s keep an eye on it an buy extra before you need it.
Of course I'm assuming this isn't an outright scam? It is from your current host I assume?