Your maximum loan amount is $1,000 or your current net worth (whichever is higher). So if you start out with $100, no lots, no items, your net worth is $100, your maximum loan amount is $1,000. If you have a $1,000 lot with a $200 personal spawn and a garage containing a $2,500 vehicle, your net worth is $3,700 and your maximum loan amount is also $3,700.
When you take out a loan, you incur a debt of the loan amount plus 10% lifetime interest (no compounding). So a loan of $1,000 incurs a debt of $1,100. You cannot take out a loan while in debt.
At the end of each tick, the amount of taxable income you made during that tick (ie, all income that wasn't given to you directly by another player - item sales, bank deposits, resources sold, etc.) is totalled and 25% of that automatically goes towards paying off your loan. You can also go and manually pay from the appropriate facility, or adjust the amount (25% to 75%).
If over a period of ten ticks you pay less than 2% of the loan five times, you are considered to have defaulted, and your property will be repossessed to cover the remaining debt, beginning with banked money, then lots etc. as detailed above.
So you take out a loan of $1,000, incurring a debt of $1,100. You must pay off 2% of this loan, or $22 per tick, to remain above the default threshold. If you don't pay enough one tick, that's a black mark, and if you have five black marks in ten ticks you get repo'd. If your income per tick is a static $48 wage (after tax, in this example your taxable income is $60 and the tax rate is 20%), you will pay $12 per tick automatically - incurring a black mark each tick and defaulting unless you adjust the rate of pay to 46% or above (help i suck at math), or pay manually each tick. So you'll be living pretty frugally until that loan's paid off.
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