Every licensed lender in the country has to adhere to the prevailing laws pertaining to rates of interest. Unlicensed and unregulated lenders can charge any amount of interest they want but banks, financial institutions and even private lenders who are registered cannot. There are specific caps on rates of interest chargeable for secured and unsecured loans. The regulation pertaining to annual percentage rate or interest applicable in case of unsecured loans such as payday loans is more lenient and hence lenders can charge much more. Banks offer secured loans that have much less interest.
APRs or annual percentage rates are not static. They are always dynamic. Not only do you get to choose between fixed and variable rates of interest, the exact annual percentage rate offered to you may not be the same that another borrower has to bear. The rates of interest vary quite substantially among borrowers, especially in case of payday loans and other types of unsecured short term loans. Even mortgage rates can vary but banks do not usually go for a substantially dynamic approach. They have stringent eligibility criteria that regulate lending so they do not have to explore the entire spectrum of interest as permitted by the law.
Lenders of unsecured short term loans assess the risk of lending money to a borrower on a case by case basis. Someone with a better credit score will get a lower rate of interest. Someone who has borrowed money from a lender in the past and has repaid on time will get more favourable terms. Someone who asks for a smaller loan amount and chooses a convenient repayment term given their income and employment will also get a better annual percentage rate. If a borrower is deemed to be a risky individual for the lender, completely from the perspective of the loan and certainly influenced by the income and employment, then the annual percentage rate is adjusted accordingly.
All private lenders of unsecured short term loans have the right to charge any rate of interest as long as they do not breach the capping as per regulation. It is fair to infer that all lenders exercise this right they have. Some lenders are more assertive with their exercising this right and can put forth exorbitant rates. Some lenders are more reasonable when they raise the annual percentage rate. Since the APR is dynamic, the lowest rate you get may or may not be the least interest applicable for the particular type of loan.