The true value of the Dollar is measured against gold. Gold doesn't change value. When you see the price of gold going up that means that the value of the dollar is going down. Inflation is what makes the Dollar worth more or less. Every time the Federal Reserve (which is a private bank, BTW) creates Dollars, like these trillion dollar stimulus plans and bailout plans, for example, the number of Dollars in circulation increases and the value of each individual Dollar decreases. The Fed is essentially counterfeiting US currency making it worth less each time. They can do this because the US Dollar is no longer backed by gold and silver.
Another problem with inflation (legal counterfeiting) is that foreign holders of Dollars see that the Fed is printing more money and making their Dollar holdings worth less (Economists estimate that there's about 5 trillion US Dollars in foreign banks). So those holders of Dollars attempt to get rid of those Dollar reserves in their countries by buying gold, real estate, oil, etc. When they do, those Dollars now flood the "market" in addition to the inflated Dollars that the Fed created. Now the value of the Dollar drops even further.
When the Yen becomes more valuable than the Dollar that means that the Japanese politicians are tightening their money supply and the US politicians are loosening it. In other words they are not counterfeiting their Yens as fast as the US Government is their counterfeiting Dollar (all governments do it).
Why does the government do this you ask? The government only has three sources of income:
- Taking it from you through taxes.
- Borrowing it.
- Counterfeiting it (inflating it)
Well, they can only tax you so much before you snap and they can only borrow so much before their credit rating sinks into an abyss. But they can unwisely print up as much as they see fit. No government entity makes money or comes in under budget (the US Postal Service and Amtrak each lose over a billion dollars a year). But the politicians have to pay for all the stuff they promised you while they were running for office.
My advise: if there is something you want to buy that may be on the edge of you price range you should probably get it now. The current Administration and Congress are on an inflation frenzy. Prices are only going to go up.