US Banknotes

There's no such thing as a "Los Angeles" $100 bill. All US bills are printed in Washington or Fort Worth, and the westernmost Federal Reserve District is based in San Francisco, not Los Angeles.

In any case any legitimate replica will be required to have numerous obvious differences from a real bill including the word COPY or REPLICA clearly displayed on both sides.

Any copy of a bill that's so close to the real thing that it can't easily be distinguished goes by another name - counterfeit. Fakes of modern $100 bills generally won't contain the fluorescent security strip reading "$100" under UV light, nor will they have a good watermark or microprinting around Ben Franklin's image. However there are some very good fakes out there so you may need to use one of the special pens that changes color when applied to real or fake bills, and / or have it checked at a large bank.

There are many superstitions and myths about US $2 bills, almost none of them with any basis in fact.

Unlike many other countries, the $2 denomination rarely circulated after the early 20th century. Various historians trace this to the fact that during the late 19th century two dollars was a common betting amount at race tracks and for, uh, "payment for services" in brothels. Many people refused to accept or spend the bills, fearing that others would assume they'd been frequenting those activities.

As time went on the association between $2 bills and vice morphed to the fiction that the bills themselves somehow became tainted by that use (!) In parts of the country, especially those with stronger religious beliefs, some people would wash $2 bills to "cleanse" them while others would tear off a corner to "let the evil escape".

These and other misconceptions caused a cycle of reduced use and reduced demand, to the point where the Treasury temporarily suspending printing after the 1963 series. That scarcity led to yet another set of myths and misunderstandings even among people who were otherwise well-informed:

• The denomination has been discontinued. False; printing resumed in 1976 and new series have been printed every few years since. As of this writing the newest series was issued in 2013.
• The denomination has been formally withdrawn. False; the bills are now and always have been legal tender.
• $2 bills are rare. False again. While they only make up about 1% of all bills in circulation that still amounts to several hundred million bills printed since 1976.

Interestingly, the United States is the only major country where a $2 denomination or its equivalent fails to circulate. $2 coins are common in Canada, Australia, and NZ, while Britain has £2 coins and the EU has €2 coins. Failure to use the denomination has a number of negative consequences for the US including increased printing costs and waste associated with the need for huge numbers of $1 bills, but continued public misunderstanding as well as opposition from the company that makes the paper used for $1 bills remain significant roadblocks to wider circulation.

For political reasons, US $1 bills haven't undergone a major redesign in over 80 years.

The underlying paper gives them a slightly gray background.

The front of the bill is printed in black ink while the seal and serial numbers are in bright green.

The back of the bill is printed in green ink.

$1 bills dated 1957 and earlier were similar except that the seal and serial numbers were generally in blue ink, although other colors were used for special issues.

Other denominations:

$2 bills follow the same pattern as $1 bills.

$5 bills have the dominant colors purple and gray

$10 bills are red, orange, and yellow

$20 bills are green, blue, and peach

$50 bills are red, white, and blue

$100 bills are blue, copper-brown, and green

As of 11/2011 approximate prices are:

Circulated: $75 to $150 depending on the bill's condition

Uncirculated: $350

Serial Numbers

A bill's serial number is a counter and a security feature. In most cases it doesn't affect a bill's value or help to identify it. Some collectors specialize in bills with low serial numbers (e.g. 00000005) or unusual patterns (12344321) so these can bring above-average prices.

DISCLAIMER: The values quoted are market averages as of the date shown, but may be different for an individual bill due to variations in quality and other factors. Also the wholesale (buying) price of a bill will be less than the selling (retail) price. A reputable currency dealer will be able to give a more accurate valuation based on an in-person inspection.

The last $2 red-seal silver certificates were printed in 1896. Nearly all red-seal $2 bills printed after that date are United States Notes, as indicated by the banner across the top of the bill's front.

There's more information on values at the Related Question.

US Notes were bills issued directly by the federal government instead of through the Federal Reserve System. They were obligations of the federal government but did not have silver or gold backing. US Notes were discontinued in the late 1960s as a cost-saving move because they were functionally identical to Federal Reserve Notes.

The US printed three denominations of silver certificates in the 1934 series:

• $1 (1934 only)
• $5 (1934, and '34A through '34D)
• $10 (1934, and '34A through '34D)

The 1934D series bills were actually printed in the late 1940s.

The 1934 series date is also of particular interest because special $1, $5, $10, and $20 bills with that date were issued for use in Hawaii and North Africa during WWII. Hawaii bills had brown seals and the name HAWAII printed on both sides. North Africa bills had yellow seals. Those distinctive colors were used so that if any bills were captured by the enemy they could be declared worthless without affecting the paper-money supply on the continental US.