What price guides do you use to value your coins? Why?

myself i have a 2008 redbook..

I use the Red Book because it's widely accessible and widely recognized, though I'm sure there are better sources.

I get Grey Sheets from a friend in AZ. They're usually a month or two out but close enough.

For world coins I use Standard Catalog of World Coins

Paper money I use Standard catalog of World paper Money

US coins and paper, I haven't bought anything in a while

I only have the one and that is Spink Coins of England and The United Kingdom 2007. Shame that the prices for hammereds are exaggerated...

Red Book for US coins

Friedberg book and Black book for US Currency

Heritage archives for trends for both

Dealer websites for comparison shopping

I usually just check ebay or Heritage auctions or one or two dealers that I trust.

Whatever the library has, eBay.

This is a favorite topic of mine!
I am a Darksider at heart and say it proudly. But I also like the lightside, grayside and occasionally the farside.
Until I find something else that covers all that under one umbrella, I use the Krause catalogs. Oh sure, they have their problems, but are still the best answer for me.

Redbook, Coin Values, & Numismedia for U.S. and Krause for international.

From my perspective these are just guides no more no less. Pricing definitely varies from region to region even within the same market as I've seen some coins cheaper on the West Coast than the East Coast and vice versa. So no "one" guide can ever capture these price variations even on an annual basis.

Redbook for US coinage. Although I don't use the prices within it very strictly. Use it just like it's called, a guide. It's too hard to keep up with the changing coin market to follow the book perfectly.

Krause mostly. Though I usually only check it when the coin arrives to see whether I got cheated.

I start with the Red Book. Then go to the PCGS web site and look at thier prices. Then I go to a few coin dealer web sites like Millersmint. Then I check out ebay. Then after writing down all those and a few more prices I say to myself, SELF, what are you doing? I then take all those prices and throw them away. Since I'm not planning on selling any coins, why worry about what they may or may not be worth.

I wait several months then send for the "refill" of the seven "newsletters" (GREYSHEET) -- costs just $13.75 -- then try to buy as close to "BID" as I can get -- it's the only real 'heartbeat' of the industry. orders@greysheet.com

I use
Spinks for British
MacDonalds and Renniks for Australian
Krause for World

I have an extensive Numismatic Library for research and I go into various auction house archives to check availability, prices and movements - also handy to see whether a coin has been "re-graded' if you are following up on provenance.

I also keep the auction catalogues for any auctions I attend or put postal bids on.

WOW! Sounds like you take coins seriously.

I only use past auction results because those are the only real prices.
With guides you have no ideas where the numbers come from and who is making them up and why.