Is there any point in paying for a chess openings book, to a depth of 10, when you can get it for free?

Try explaining please.if you like.

I dunno what tonydal meant?  But in a book the author will give some explanations, and useful side lines.  Maybe they note one line has a lot of theory in it, and so can recommend a lesser tried, interesting, and equally playable move on move 7 (or whenever).  They also have many example games.

Also the book may cover a variation that you didn't know existed.  Or the opposite, if you're only using a database you may spend too much time looking at older lines that have fallen out of favor and not enough time looking at modern lines you're more likely to face today.  So information overload and you're not sure where to begin or end.  A book does all the foot work for you, all you have to do is sit down and memorize (essentially) and you'll come out with a solid repertoire.

Good point, a book will give additional information, but the temptation to get it for free is always attractive.

I definitely agree :) and remember those books aren't going to help you one bit after the opening is over.  Lets say I was on an island and could choose any 5 chess books, none of them would be on the opening for sure.

[re-reads OP] heh, yeah you're right, I didn't even catch that... it reads completely rhetorical :p

Because just by looking at one or two lines 20 moves deep with an added explanation to the overall plan of your middlegame you will understand what to do after the opening is over (this is very under rated imo). Even if the opening goes out of book after move 7 you can still apply many of the ideas and plans by having that 20 move line in your head.

By free i mean via a website, you pay your I.S.P.

I'm up for a game of tetherball.

I agree with orangehonda, you can look up the opening moves free but you don't really get the in depth analysis of just what that opening does for you in the latter parts of the game that a book offers.

Wikipedia gives explanations.

You have got to be kidding me. Those piles of junk don't qualify as explanations. They're just sub-standard descriptions of about 10% of mainline moves.

Sometimes it's up to $30 for a book, maybe we are dopey dupes