"Usurious" means lending money at a much higher interest rate than anyone else, or charging more than anyone else.
These rates are usurious - I am going to Citibank instead!
Use it's (with the apostrophe) only when you mean "it is" or "it has." For example: It's time to go. (It is time to go.)It's been a long time. (It has been a long time.) Use its (without the...