How do we have a fun, but affordable wedding in Sydney?

My fiancé and I are looking to have our wedding in feb/mar 2019. Based on what we would both like out of the reception (sit down meal with great food, central dance floor, fun atmosphere for our guests), it is quite hard to find something that doesn’t break the bank. We have roughly 100 guests. Also taking into account we would like the venue to look nice with some decorations etc. we would also like something in Sydney. Any suggestions for reception venues??