Everyone has different size of hands, so you have to find a coin that suits your hand. If you are one of "coin manipulator", using a coin that suits your hand is extremely important IMO.
One good thing about learning coin magic is that there are a lot of different sized coins out there.
If you have thin and long fingers, you can basically pull off any kinds of coins, lucky bastard. However, if you have any other types of fingers, you have to carefully choose your coin, unless your fingertip work will look like a piece of #2.
The reason I say thin and long fingers can pull off any kinds of coins is that these fingers can handle larger coins because of long fingers but also can handle smaller coins such as half dollars because of thin fingers. If half dollar is held by chubby fingers, it looks smaller and it is not as visually stunning during any fingertip coin work.
Unless you are a lucky bastard, you have to invest your time and money to find the right coin. The way I choose my coins is by trying them out in my high finger palm(if you do not know what high finger palm is, it is where you palm a coin with the upper joint of your fingers). I choose the largest coin I can high finger palm while it doesn’t make my hand crooked.
If the coin is too small for your high finger palm, it is definitely too small for you. It will make your fingers look like they are holding something when you are doing certain sleights. If you cannot hold it in your high finger palm because the coin is too big, you are either going to flash all the time or your fingers are going to look crooked because you are going to try very hard to not flash.
Always try to use coins with a reeded edge because it makes certain moves easier. Certain coins have a smooth edge so I always drop them; I cannot even do certain moves with them. By the way, barber half dollars usually have smooth edges but it is ok to use because they still have great grips. I don’t know why.
I think the most inexpensive way to find the right coin is to go to your local antique shop and try out all the coins they have. If you are lucky enough, you are going to find one at a great price. When you show owners a couple coin routines, they might even give you a discount :P
If you are lazy and never go out of your room and shops everything on the internet like me, here is a solution for you. Uhhh… Before I give you instructions, here is a chart of diameters of coins. For various coins. Although it is not a complete chart, it can be pretty useful when you are looking for coins.
Just do a quick research if you want some exotic coins if you want to tell stories to your spectators.
*I got most of the information on this chart from Xavier Belmont's website. A great craftsman.
Since you like coin magic enough to read my blog, I assume you at least have some kind of half dollars or dollars somewhere in your room. Try them out and see if they are just PERFECT for you. If not, check out their diameter and estimate which one you would like to use for rest of your life using the chart.
Another way is to cut out a piece of cardboard and use it to see which size is good for you.
Good luck finding your "soulmate coin", people. eBay is always your best friend.
FYI, my favorite coin is size reduced eagle dollar. It is a little smaller than normal eagle dollar. Those are from eagle dollar deans set. However, my EDC(Every day Carry) coin is usually normal eagle dollar or normal 50 Francs. Occasionally, when I go to somewhere, not as “safe” such as camping or a short trip, I carry morgan dollar because I don’t like this coin and I bought it when I was just exploring, so I don’t care if I lose it. However, it still makes me look cool I guess haha
I personally do not like too “silvery” coins such as Morgan dollars because I cannot do certain moves correctly with them. I’d rather prefer Eisenhower dollar because it is more slippery.
PS: I use sand paper to soften out eagle dollars because it has too much of details on its face and back which enables me to do certain sleights.