Assuming you're referring to U.S. bills that were found in circulation, nearly anything dated 1977 or later would be worth face value only.
If the bills are uncirculated please post separate and more specific questions, one for each year and denomination.
Yes. The US has never withdrawn or demonetized any bills except for gold certificates. 1995 and 1999 bills are sufficiently new that some of them remain in circulation.
There were no 1990 $1 bills, but anything printed since the late 1980s is only worth face value even if it's uncirculated. There have simply been too many of them printed to be worth more. The only exception, of course, would be error notes such as foldovers, offset printing, etc.
Face value only. It's too new and too many were printed for it to carry a premium.
US bills are printed in at least 3 separate stages, so the error you describe could happen if a set of bills accidentally fails to go through one of the phases or is flipped over so the seal is printed on the other side. In any case these are considered to be major printing errors and could be worth several times face value. You'll need to check with an expert on paper money who can look at your bill in person for a more specific valuation.
Face value only. It's too new and too many were printed for it to carry a premium.
No. During that decade the U.S. issued $1 bills with dates of 1993, 1995, and 1999.
Please check again and post a new, separate question. No US bills were dated 2000, and Susan B. Anthony's portrait appeared on $1 coins minted in 1979-81 and 1999. All US $1 bills printed since the early 20th century carry the familiar picture of George Washington.
one: bills bills bills in 1999
Through the 2008 season, the last time the Bills made the playoffs was 1999.
Although 1999 and 2000 remained relatively strong, value of shipments dropped dramatically in 2001, sinking to $5.3 billion, the lowest since 1995.
Like all modern $1 bills, a 1999 US $1 bill is worth one dollar. If your question is asking if it's worth more than one dollar to a collector, these bills have no added value unless they're in the best possible uncirculated condition.
Please check your bills again and post a new, separate question for each date. The only dates in that range are 1999, 2001, 2003, 2006, and 2009, and all of them have green seals. The last red-seal $100 bills were dated 1966.