It depends on how fast money is created versus how fast the growth in goods and services is. If goods and services grow faster than the money supply grows, then prices decline over time. This is really painful to people who have borrowed money and have to do more work to pay it off. If the money supply grows at the same rate that goods and services grow then prices are stable. If the money supply grows faster, we have inflation which we are currently experiencing. If the FED can rein the US money supply growth back to levels closer to the growth in goods and services, then it can go on indefinitely.