Here's the deal on Pappy. 5 years ago I could walk in and buy 10-20y all day long, if you knew where to go. I would pay retail for 10 and 15y, and a $50 premium for 20y and a $75-100 premium for 23y.
Sans-Pappy theft, it's more popular than it needs to be. People camp out 2-3 days in advance of the release date, for a store that only gets an allocation (3 - 23y, 6 - 20y, 24 - 15y, 60 - 10y). I have gone from my son's carpool line in the morning to the liquor store an hour before opening, and was #61 in line, and paid retail for 10y; 1-9 were there for 3 days. I called a liquor store owner friend and got another bottle at retail. Called another friend and paid a $50 premium for another 10y bottle. 23y has a value starting at $2k and up to $4k; 20y $1k-4k; 15y $1k-2k, 10y $400 is a good average price around here. The only reason I don't sell any of my bottles is because I actually drink it and enjoy it. I've never paid more than $300 for a bottle of any year. My #2 is Four Roses Small Batch. My commercial drink whenever (and a bottle usually in the back of my car), is Buffalo Trace. If you are looking for Pappy Taste, without the price, I recommend Weller. You can find it about anywhere outside the state of Kentucky for <$50 (many people here will refill Pappy with Weller, and serve it). The Weller 12y and Pappy 10y taste almost identical. It's the same distilled spirit, just a different shelf in the barn. Blanton's is also produced at the same distillery. Another contender to similarity is Old Weller Antique 107. For an overview of most of the bourbon's, look at the Bourbon Tree. It'll show you the relations. http://visual.ly/bourbon-family-tree