The good thing about this hobby is that, if I can't find what I'm looking for RIGHT NOW, there is always something else I can buy. The bad thing about this hobby is that, if I can't find what I'm looking for RIGHT NOW, there is ALWAYS something else I can buy. So yet again, I attempt to learn about something new in addition to U.S. coins: Which denominations/years would be best to start with? Wikipedia says "The most common large-sized notes are the Federal Reserve Notes of Series 1914 and 1918." But if I want one that looks pretty much like modern notes, except larger, then I want "Silver Certificates"? They don't have to be mint condition. I like to buy problem-free specimens at a grade that can more easily be sold down the road. All items usually have a steep increase in price at a certain grade; I like to buy at the grade just before that big increase. Your assistance is appreciated. Thank you.
Most common doesn't always equate to greatest survival. Cheapest is the 1923 $1 Silver Certificate: This note can be had for about $20 in a problem-free mid grade. The steep price increase usually occurs right before CU grades. You can buy one in XF-AU for $40-$50.
Wikipedia is right that small denomination large FRNs can be had for a modest sum, as long as they are from ciommon districts, with common sigs, and of course, are blue seal. I've even gotten a few $50s pretty cheaply. As I stated in another thread, 1917 $1/$2 United States Notes are inexpensive in circulated grades. These prices start to creep up after Fine/Very Fine, and start getting expensive after Extremely Fine. Also, 1922 $10/$20 Gold Certificates can often be had for a C-Note in VG/F. Whatever tickles your fancy. If you can afford to spend $300 on a note, things really start to open up, both in terms of series, denomination, and grade.
I live by this motto; Always buy the best note that you can afford, if you can not afford a CU graded note, then save your money until you can because you will loose on the resale in the majority of cases. Just my two cents here...