is incorrect.
You need:
appArgs.push(algosdk.encodeUint64(price)));
See Byte to int (vice versa) conversion and comparison in Teal - #5 by pagito
is incorrect.
You need:
appArgs.push(algosdk.encodeUint64(price)));
See Byte to int (vice versa) conversion and comparison in Teal - #5 by pagito