I am unsure what price I should offer or how I should approach it???
Unless you decide to leverage the time, skills and knowledge of a buyers agent, you need to learn Box Hill inside out yourself. You should get to a stage where you are reasonably able to predict sales prices with some degree of accuracy. Watch the market for a few months, visit LOTS of properties, note the actual sale prices and see how you are tracking. Once you have this level of knowledge, you can spot bargains if they exist. If not, you will still be able to accurately determine the market price for a given property in your area.
further more as an example, if my research indicates that the recent sales indicates that the property would be worht approx $435... how should I approach making offers????
This is simpler than you think. If you think it's worth $435k and they are asking $420k-460k, why not call up the agent and offer $420k to start with? Most PI books have sections on 'how to negotiate' if you are looking for specific tips. My personal view is that if you overpay slightly for a quality asset it's no huge deal.