Loan schemes, credit card traps, investment scams.

1. Loan tricks: Some lending institutions will use low-interest loans as bait to attract people to apply. However, after the borrower applies, the institution will raise the interest rate or charge fees for various reasons, causing the borrower to repay more debt.

2. Credit card trap: Some credit card issuing banks will use low interest rates or preferential terms to attract people to apply for credit cards. However, during the use of credit cards, banks will suddenly increase interest rates or cancel preferential conditions, causing borrowers to repay more debt.

3. Investment scams: Some investment scams also use the trick of "borrowing less first and then borrowing more". Scammers often lure people with the promise of a high rate of return to invest smaller amounts. However, after defrauding a large amount of investment, the scammer will suddenly disappear or refuse to return the investment for various reasons, causing investors to suffer heavy losses.