Matt, that is probably a pretty good estimate of the going rate...
One sold on eBay over the weekend for $199 and it was marketed as being in "good condition."
If you are going to pull the trigger and buy one at the price point, you may want to consider yourself lucky - a couple of years ago it was hard to come by copies for less than $500 and I believe I saw some that were selling for over $700 on eBay. Keep in mind there are a couple of editions out there, I believe the one that was produced in the highest quantities has a yellow dust jacket and was printed by Sleeping Bear Press. I believe the very first edition has a burgundy cover with gold lettering and no dust jacket - I don't believe there are very many of these out there and I believe Tom originally distributed these to his friends.
Tom Doak is in the process of writing a new Guide, but I believe it is planned in several volumes and will be released over several years. I believe the first volume is on UK courses and is slotted for release next summer. Tom frequents this site and I am sure if any of the above is incorrect, he will follow-up with the right information. Some speculate that with the new Guides coming out, this will drive the going rate of the ones in circulation today down, but if that happens it won't be for a little while yet.
I have a copy and I do highly recommend it - it continues to be a great resource and a book I pick up at least once a month to look something up or just to flip through...