Red Book Valuations For Newbie

RB prices are about 20% high and out of date the same day the book comes out. Check eBay sold values and here:http://m.numismedia.com/rarecoinprices.htm
For high end coins check auctions houses sold values.
John1

Yes, the Red Book pricing is a good general start for retail pricing he might pay if he wanted to buy and as mentioned used also for relative pricing meaning which coins are more rare or desirable to look for over others which is also good for beginners. There are a number of online sources for similar pricing, one link given by john1.

Dealers need to make a profit to stay in business, so if you go to sell your collection to a coin shop rather than sell direct to other collectors, auction house or similar, you're not going to get those Red Book prices which again are somewhat the prices they might sell for (but may be off due to the age of when they gathered the info). There is another version most don't talk about, the Blue Book which deals with wholesale coin values. These are the average values a coin dealer will offer to pay you for your coins (again generally as its not as up to date as other sources used these days such as greysheet pricing). They typically run between 50% and 75% of what the exact same coins would sell for at the retail price so as mentioned a 50%-75% of the Red Book might be an estimate to start what you might get from a dealer generally. Coins that derive most of their value from bullion like American Silver Eagles might get you different values like spot +/- something because most of their value is based on the silver or gold itself, rather than the rarity of the coin unless its one of the special editions/graded etc and the dealer doesn't ignore the potential added value of that for just the metal value.

Most people in the hobby pay wholesale and RedBook is full retail pricing. If you buy a roll of VG and better '09-VDB cents they are far cheaper than if you go into a coin shop, pull out your list and ask for an '09-VDB in VG and a '22-D in AG. If you want specific coins and don't make an offer when you see one then you'll probably pay retail or somewhere around RedBook.

None of this applies to moderns because RedBook grossly underprices them, nobody wants them, and most coin shops don't stock them. RedBook prices some moderns so low that it stifles any trade in them. It's doubly harmful to these coins because many of the buyers are perfectly willing to pay retail prices. The dealer isn't going to have a Gem '82 quarter for any price and if he actually tried to sell one at the $15 RedBook price it would have been scooped up by someone who knew its value long before you got there.

I am relatively new to the hobby (or at least, new to taking the hobby seriously). The Red Book-style price guides were useful to me as a quick way to scan a list and identify coins that were of interest. Most of the articles out there are flavored like "Top 10 Jefferson nickels for Big $$$" or "Shocking $5000 Error Coins That Might Be in Your Pocket!". Other coin dealer lists will catalogue everything exhaustively on a site that is overwhelmed with blinking, busy social media ads. Typically they are not in an iPad-friendly format anyway. At least the printed guides are concise. There were two available for free at my local library.

Finding a good summary without sensational junk has actually been a real challenge. Even books like the Bowers guide have way, way too much information to effectively distill into an approach to the $50 pile of circulated nickels on your desk. Is it cool to know that some MS-67 nickel from the 1980s is worth $1500? Sure, in theory.

TL;DR: I think the printed guides can be useful for rookies, just to get calibrated. It's a starting point, not the final authority.