I sell wine from £5 a bottle to £whatever. Most expensive bottle I have on hand to poke is about £700. The decent stuff is generally kept in bond as it should be.
As mentioned above
www.wine-searcher.com is a good place for price finding (ignore everywine.co.uk). Other internet resources I use regularly are:
www.cellartracker.com - community reviews
www.erobertparker.com - Both Bob himself & Neal Martin - formerly of wine anorak. Forums are free. I have a sub as it's very handy
www.wine-pages.co.uk - Tom Cannavan + UK community forum
www.wine-journal.com - Jamie Goode - wine scientist chap. I have a couple of his books.
www.winedoctor.com - Chris Kissack - world renowned expert on Blue Nun.
Cheval Blanc is an interesting one. Most vintages are rated good to excellent by Bob P Jnr with a couple of shockers and a couple of perfect 100s. The price will be high for any vintage but vary a lot according to his scores. Cheapest winesearcher price for the 2000 vintage is £450 ex-VAT - although Fine & Rare are at £589 and they are much more likely to be up to date and actually have some. Conversely the 1997 is a bit **** and sells for £154 ex-VAT. I could show you dozens of wines around £10 that get better reviews than this 1997 wine (terrible year in general and one where the Bordelais shot themselves in the collective foot post '95 & '96 price hikes) but it's Cheval Blanc....
Wine is wine to some people. I read reviews of wines I've tried and liked and they aren't always favourable. The reasoning is to align my palette (or pallet in the Sun's wine column this week) to a critic's. Once I know what I like about a wine and how that affects a certain expert's reviews & scores I can make more informed purchases. For example, I like traditional style Bordeaux as opposed to the often higher scoring overly spoofulated wines produced by winemakers who are seeking high Parker points. Because as Dale has taught us: "Points mean prizes" (or prices in this case).
I'm currently drinking a glass of Ozzie Shiraz that set me back about £5 for the bottle. It's rather nice. Tomorrow I'm having dinner with some family and will be dipping into my cache of good stuff. Pontet Canet '95 is a likely candidate.
Addendum: Parker's scoring is becoming increasingly odd and the tasting notes more important. Up to May 2005 there were 140 100 point wines (source: google 5 minutes ago) in total - from 1980(ish) when he started until then. This week he has rated 10 2007 Châteauneuf-du-Papes at 100 points.