The cost of putting money into something for a certain time is ALWAYS equivalent to borrowing that money.  Because you have to compare using the money the way you intend, with lending it out.

If you had to spend $1000,- and not have your product finished for a year, and interest rate is 10%, then you COULD HAVE OBTAINED $100 by lending it out during that year (placing it on a savings account, say).  So if you spend it on something, and you can sell your product only one year afterwards for $1050,- you have essentially LOST $50, as compared to putting your money on a savings account at an interest rate of 10%, or by lending it out at 10%.

Inflation or deflation has nothing to do with this.  If your return on investment is LOWER than the market interest rate, you lose in using the money for your investment.  You better put it on a savings account.

So you should always, if you need money in an example, consider that you borrow it.