No standard range. Basically creating the smartcontract was so cheap but the problem is how many funds that already owned to backed your stable token. If you own nothing and im sure that your stable token was just another useless token. There shall be a fund to backed your stable token. This will be using the fiat money as a way for you to create stable token. In my opinion that if there was no standard for this. The range was random but this is also totally depend with the reputation of yours.