An Australian 1954 to 1961 Ten Shilling note (Coombs/Wilson)(depending on the serial number), uncirculated and in absolute mint condition could fetch anything from $400 up to $32,500 AUD. If it has been circulated but still in good condition, it might fetch anything from $25 to $18,500 AUD.
A reputable coin dealer will be able to give a more accurate valuation.
A Commonwealth of Australia Ten Shilling note (Coombs/Wilson)(serial AG), uncirculated and in absolute mint condition could fetch up to $450 AUD. If it has been in circulation but still in good condition, it might fetch anything from $25 to $200 AUD.
A reputable coin dealer will be able to give a more accurate valuation.