Cheryl,
In my opinion yo would be best off doing what Simon has said and buy a place with the 20% deposit so that you avoid LMI. However, I would only buy a property worth less than $150,000. That way, you can buy potentially 4 of these properties (deposit of $30,000 each + room for expenses). That way you are minimising your exposure to risk in case you were to lose a tenant.
For example, if you have one property renting for $500 per week and you lose that tenant, then you are $500 our of pocket for each week you go without a tenant.
However, if you have 5 properties each renting for $100 a week. You still have a total rental income of $500 per week, however if you were to lose a tenant you will only be out of pocket by $100 for each week you are without a tenant.
I think that makes much more sense than buying one expensive property.
Good Luck!