Rightflyer

The example is trying to say that $3000 amortized over 10 years (120 months) is $25 per month. 

Ironically, the math is still incorrect.  It isn't 0.3% per month.  It works out to 0.025% per month. But it is 0.3% per year if the $3K is spread out over 10 years. 

It is actually more complicated then that, because if you spend $300 per year the balance is still in the account growing until the next year, vs spending $3000 in year one then amortizing that cost over 10 years.  The comment does not consider the time value of money.