My Red book is old but a good 1920-D is worth $12. I don't know the grade. It isn't in XF grade. I don't know if it isn't good.
Did you end up selling the Buffalo Nickel? If you tried to sell it to a dealer, then I think you'd get hosed on it (probably $5-$7, if you got bids at all). They will look at the rim merging, especially around the mint mark and just automatically treat it like a G-4. When looking past the rim merging, the coin definitely has details that justify a Fine grade. With that in mind and based on the recent pricing I see on eBay, a 1920-D in the condition those images show could fetch something in the $15 to $25 range depending on who is selling it (as in, do you have any prior sales or reviews that would establish trust). Why not higher, if the retail price of a Fine 1920-D Buffalo Nickel is $65-$90? From what I've experienced selling online, ungraded, low-grade coins need to be discounted way below the "retail" / Redbook / PCGS prices. I've generally discounted my ungraded/low-grade coins 40-50% below retail and they tend to sell quickly. If I were selling it, I'd list it for $24.95, leave up the Make Offer functionality and be willing to accept down to $18. If I had no bites, I'd slowly lower the listing price to $19.99 over a period of two weeks. and drop my lowest acceptable offer to $15. Most importantly, I would not do an auction for it. The low-grade Buffalo Nickel auctions perform really poorly of late. Also, your title needs to hit all the important key words and there would need to be a short but powerful description justifying the price. In case you want to roll the dice and try to list it higher, I uploaded a detailed analysis report of the coin that might help you sell it for more (could help you with your description). Best of luck!