Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

What is inflation?
When we speak about a product or service, we generally refer to its value. Currency, while neither a product or service, has its own value. As the value of currency goes down, the price of products bought by that currency will go up. You could consider the price of a product or service the value of the product multiplied by the value of the currency. For your first example, we compare two cars, one bought in 1990, and one bought in 2015. Each car has the same features (AC, radio, ABS, etc). We can say that, when these products were new, each had the same value. However, we can deduce that since the 1990 car cost $100, and the 2015 car cost $400, that there has been 75% inflation over 25 years. Comparing prices over time helps identify the inflation (or devaluation of currency) that an economy is experiencing. In regards to your second question, you can say that there was 7% inflation over five years (total). Keep in mind that these are absolute cumulative values. It doesn't mean that there was a 7% increase year over year (that would be 35% inflation over five years), but simply that the absolute value of the dollar has changed 7% over those five years. The sum of the percentages over those five years will be less than 7%, because inflation is measured yearly, but the total cumulative change is 7% from the original value. To put that in perspective, say that you have $100 in 2010, with an expected 7% inflation by 2015, which means that your $100 will be worth $93 in 2015. This means that the yearly inflation would be about 1.5% for five years, resulting in a total of 7% inflation over five years. Note that you still have a hundred dollar bill in your pocket that you've saved for five years, but now that money can buy less product. For example, if you say that $100 buys 50 gallons of gasoline ($2/gallon) in 2010, you will only be able to afford 46.5 gallons with that same bill in 2015 ($2.15/gallon). As you can see, the 7% inflation caused a 7% increase in gasoline prices. In other words, if the value of the car remained the same, its actual price would go up, because the value stayed the same. However, it's more likely that the car's value will decrease significantly in those five years (perhaps as much as 50% or more in some cases), but its price would be higher than it would have been without inflation. If the car's value had dropped 50% (so $50 in original year prices), then it would have a higher price (50 value * 1.07 currency ratio = $53.50). Note that even though its value has decreased by half, its price has not decreased by 50%, because it was hoisted up by inflation. For your final question, the purpose of a loan is so that the loaner will make a profit from the transaction. Consider your prior example where there was 7% inflation over five years. That means that a loan for $100 in 2010 would only be worth $93 in 2015. Interest is how loans combat this loss of value (as well as to earn some profit), so if the loaner expects 7% inflation over five years, they'll charge some higher interest (say 8-10%, or even more), so that when you pay them back on time, they'll come out ahead, or they might use more advanced schemes, like adjustable rates, etc. So, interest rates will naturally be lower when forecasted inflation is lower, and higher when forecasted inflation is higher. The best time to get a loan is when interest rates are low-- if you get locked into a high interest loan and inflation stalls, they will make more money off of you (because the currency has more value), while if inflation skyrockets, your loan will be worth less to loaner. However, they're usually really good about predicting inflation, so it would take an incredible amount of inflation to actually come out on top of a loan.