When I first started advising people on naturalisation back in 2012, the application fee was $84. This has crept up over the years. By 2016 it was $250. In 2018, it was $500. And in 2022, it was increased to $1000!
So there is always a risk that, come the new financial year on the first of April, the fees will go up again. If you or a family member are in the position of being eligible to apply for naturalisation prior to the 1st April, it may be worth focussing on getting it submitted prior to then, as it could save you hundreds of dollars.
For PRC, there are slightly different considerations.