The explicit goal of the Federal Treasury is a 2% inflation rate in the U.S.. They estimate inflation based on a core set of goods, and ignore everything else, which is why inflation seems so off. Inflation the way most people think about it isn't really a thing: money doesn't have blanket buying power in terms of goods.

Think of it like this: we have a range of wages, with a median income. Those wages are dollars per labor hour. If we double them all, immediately, and just print up twice the money, we get 100% inflation and no change in the relative cost of goods; all the prices must go up to match (get to that next). That's what people think of when you talk about inflation: everything is priced higher, we adjust the number of dollars upward.

The thing is that's not how it works. Money isn't that kind of magic. You've seen hard drives get cheaper (from thousands of dollars for any unit--at a few megabytes--to today's pennies-per-gigabyte and $80 full units), displays get cheaper (again: thousands of dollars to $100 or so, and the screens are bigger), phones get cheaper ($4,000 for a cell phone in 1983; $350 for a OnePlus 3t in 2016), and so forth. Food, clothing, housing, medical care, these things rise in price or even in proportion of spending; yet people eat out more (food + servants), spend a smaller percentage of their income on these things (food and clothing), or spend a bigger percentage of their income while buying more than the difference (e.g. 4% of median income spending today would buy more and better healthcare than 4% of the median income bought in 1950, and instead people spend 6% of their income and buy even more).

It's not just that some things price up and others price down anyway; it's that they price up and down at different rates. Food and clothing prices both grow more-slowly than wages, and so the inflation rate of food is different than the inflation rate of clothing. Even then, different foods and different clothes change differently.

So what actually happens?

Well, the minimum viable cost of a product has a hard-bound at the wages to supply it. Imagine all wages involved in making a shirt are $10/hr, including the cotton farming, the dying, the shipping, the retail, business management to get all this organized, and everything else. If it takes a total of 14 labor hours to get that shirt into your hands, then either that shirt costs no less than $140 or somebody doesn't get paid. Get that cut down to 3 labor-hours per shirt and the shirt has to cost more than $30--at a 40% profit, it would cost $42!

That's why prices come down: the costs come down. Each business in the supply chain has some profit, which bumps those prices above the wage-labor cost; lower the wage-labor costs and the price coming out of that business is still lower with the same profit margins. The profit margins are as high as the market will bear, and reducing the minimum price possible allows another manufacturer to target consumers who can't afford your product at its current price; because existing buyers would rather spend $50 than $100, you lose business to the new guy unless you cut your prices, so the broader market forces a narrowing of profit margins by increasing the pressure from competition (either actual competitors or potential competitors by way of making it less-risky for someone to try to break into your market). Without that particular beating stick, prices would just stay high.

Importantly, people still have the same labor to trade.

Recall above I said that prices must go up if you double the amount of wages and money? Here's why.

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