Well I've been on loads of cheap flights to Genoa, Rome, Barcelona, Malmo, Dublin, etc, with fares (excluding the dreaded 'taxes and charges') generally in the range of �0.01 to �9.99.
I live about an hour's drive from Stansted, which is a major hub for Ryanair (who're frequently, but not always, the cheapest airline). Other bargain airlines include easyJet and Jet2 (but there are plenty of others - it depends where you want to fly to),
For 'sunshine coast' destinations, you usually need to book well in advance but other destinations often have bargains even at quite short notice.
The best bargains are often to be found with midweek travel. Weekends tend to be dearer. Always book directly on the airline's website, never through third party sites.
For example, I've just checked Ryanair's website for a theoretical week's holiday at the end of this month. Travelling out from Stansted to Valencia on Thursday 25 September, the flight is free; you just pay �26.85 in taxes & charges. Coming back one week later, the flight costs �14.99; taxes and charges come to �14.03. So the total inclusive return fare is �55.87. (OK, Ryanair charge a �4 fee for handling most types of debit & credit cards, but that's still around 60 quid return. Also, try to just take cabin baggage, otherwise there are additional fees for checked bags).
That example wasn't found after hours of scouring websites. It's the very first one I looked at. For the same dates, you could travel to Dublin and back for a total of just �30 (including all taxes and charges but excluding the �4 card handling fee).
For cheap flights, just start exploring the websites of the budget airlines.
Chris