I recently (~8 months) got in to coin collecting. Right now I'm still at the coin roll hunting/circulated coin stage, but one can only go through so many boxes of change without wanting, well, a change. What are some bills worth looking for? I know with coins it's older ones and newer ones in great condition, but what about bills? I'm only (moderately) familiar with star notes and nice serial numbers (repeating digits, birth year last four digits), but are what are the kind of bills you as a collector save or desire? I'd love to start doing bills too, I just don't know where to start!
What you need, and can probably find free, is a big detailed price-list from a currency dealer. You will see what look like "common" items bringing high prices, and it would make sense to search for them, or simply be aware of them. That said, the number of bills in everyday circulation, worth saving, is V...E...R...Y small, despite the tons of optimistic inquiries posted here.
Electric, mortgage, insurance, cable, oil....those are the bills I collect. Sometimes a few nicely worn Washington's are left after those for my troubles.
I think MPC's are one of the most under-rated of all the currency specialties. They are HARD to find in prime condition, and in my opinion, grossly underpriced; it's a smart thing to collect, and one numismatic item I would not hesitate to grade.
I collect French notes, because I have lots of memories of France. For me, it's important to have some personal tie to what you're collecting. If you're investing or hoarding, then different rules apply, but I like to think a *collector* is picking up material that he has a connection to. I wrote an article about it at http://www.frenchbanknotes.com/articles/collecting.php that you might enjoy reading.
I am sticking to dollar bills, the aces, large and small, but if you want to find out what notes might gain a premium besides the stars and rare serial numbers, get yourself a copy of Shwarts and Lindquist small size paper money,
I personally like... well, what I like. I am a bad collector because I tend to accumulate more than collect. That being said, right now I am on the following "kicks" in my searching: 1. French banknotes (the artistry!) 2. Small-Size Silver Certificates (the color!) 3. Federal Reserve Notes from pre-1995 (the money we got as kids when we mowed the lawn!) Get PUMPED! You are a note collector now!
One type of collection I started are notes with a mixed typeface of the letter "A" in the serial numbers. In small size notes, the transition begins to appear in the series 1928 Tate Mellon notes and ends in the Julian-Vinson era. The mixed typeface actually pre-dates small size notes and most prominent in later printed large FRNs. Above are two notes I've acquired with mixed typeface.