Compared to local suppliers Centrum Vitamin supplements are much cheaper from here.
There are various products like
Mens and Womens Ultra vitamins. Size 200 tablets for 19.99 which is equiv to 10c a tablet vs local discount supplier of 17c a tablet (120 tablet count)
The only thing to consider is the differences in composition, however you also have to consider that with every vitamin tablet sold here.
Comparison is sometimes hard as manufacturers show vitamin quantities differently sometimes mcg, iu etc. Some products are higher in certain vitamins than others, and RDI (Reference Daily Intake)is different for different countries sex and age group.
So you will need to do some checking if the composition suits you. If it does there is some big savings to be made. Also when having products shipped just remember to try and max out the weight of 3lbs, which Vitacost conveniently tells you upfront. This reduces the average cost of the shipping.
Also you can add free samples up to two each order. http://www.vitacost.com/freesamples/?ss=1
If you are a first time buyer you can save another $10 by using a referral code. You can find a number here on this site by searching http://www.ozbargain.com.au/search/node/vitacost or checking this thread http://www.ozbargain.com.au/node/60499