I suppose many pilots are like me and check what’s on the market from time to time – even if you already own a plane, you want to see what is out there, or if you fly in a club why not dream of your own plane. 
So I would be interested to know which sites you check regularly and why. My most regularly visited site is www.planecheck.com, because they have more “European” content and it seems to be of good quality.
Also, those who have bought a plane, how did you originally find it – through an ad on one of these sites, or a recommendation (i.e. “hangar talk”), or a broker?
My name is Tom and I am an addict.
I visit the /eu ads on PlaneCheck: http://www.planecheck.com/eu/
I have a bookmark for “european” planes on controller.com and on aircraft24.com
I also like visiting the British afors.com
From these I sometimes stumble over to seller’s web sites, but don’t really frequent any of those.
We found our plane in early 2011 via www.aeromarkt.com, a site that seems to be virtually dead by now.
I visit www.planecheck.com regularly – in fact, at least every second day – because it’s just interesting to see what is on the market and what people demand for it. Planecheck is definitely the (European) site with the most offers.
www.justplanetrading.com frequently has planes that seem to be excellent value for money.
Fairly recently I came to notice www.k-aircraft.de, www.wfaviation.com (run by a regular user of this forum ) and www.flyingfoxaviation.com which also have substantial numbers of interesting aircraft.
That aside, I am again and again surprised how many dealers or workshops offer aircraft without placing them on one of the major websites. This would be unthinkable eg. in the used car business.
controller.com
I am no longer allowed to look at airplane ads. 
I found mine on Planecheck, which was my first port of call for exactly the reasons you mention.
I also enjoy, er… I mean, some other forumites might enjoy browsing :
And for the health of your bank balance, under no circumstances should anyone visit Exclusive Aircraft
I was also in the habit of asking around whenever I visited an airfield – there are often noticeboards advertising locally-based aircraft for sale many of which I never saw on the internet.
My theory is that people who sell planes on the internet do exactly the same thing as women do in internet dating: they join just one site and hope that the tall dark handsome adventurous spontaneous uninhibited assertive (just listing the standard tick boxes, you understand) prince on a white horse will appear out of it and sweep her off her feet
So, people looking for planes on the internet, and guys looking for girls on the internet, need to do the whole lot. I don’t know how many plane sites there are for Europe, and how many dealer adverts there are online and in the printed rags, but when I last did internet dating (2003) there were about 20 sites covering the UK And I bet there are more plane sites than you think because Europe has a lot of different languages and there is very little mixing in terms of which media is referenced.
On top of all this, way more than 50% of owners don’t advertise their plane openly – especially if selling
so a lot of planes get shifted quietly.
There is also a good reason for a low-profile sale: you are likely to get a better price for it, because you won’t appear so desperate.
So if you are looking to buy a plane you do need to do some hard digging And more than likely the best ones will arrive by a private message.
My current ’plane I found abandoned in the corner of a hangar in Ireland, and learned I was the owner the morning after a few tinctures of the finest Wicklow Mountain spring water (95%) the evening before.
Klaus Kuhle did a fine job converting my previous complex aircraft to cash, a feat more challenging than people new to airplane ownership might not yet fully appreciate.
Barnstormers.com is a fun site, and planecheck.com has some interesting types but prices tend to be on the hopeful side. In general trade-a-plane may be the most reliable market info for American types.
G-INFO is a good source for potential interesting types that may be languishing, and looking in hangars in tucked away airfields may result in a barn find.
Peter wrote:
There is also a good reason for a low-profile sale: you are likely to get a better price for it, because you won’t appear so desperate.So if you are looking to buy a plane you do need to do some hard digging And more than likely the best ones will arrive by a private message.
However this applies to most expensive assets. Aircraft are no different from classic cars for example.
Also, those who have bought a plane, how did you originally find it – through an ad on one of these sites, or a recommendation (i.e. “hangar talk”), or a broker?
I think the best way is to become known to enthusiastic owners of the type, which provides an education on who has the best planes, and puts you in the loop when the owner of a really nice one starts ‘making noises’ to his friends. I did this for my first aircraft, and it worked out really well.
For the second aircraft I bought a local plane from a national advert, having watched it become a ramp rat for two years beforehand and guessing it would come up for sale eventually. During that period my curiosity had led me to learn the longer term history of the plane, and I liked what I learned. No other offers were made and I got it for 30% less than the asking price. That ended up being a fair deal, with some trials and tribulations over several years, but still fun.
Regardless of how you find the plane, I think studying the market and the type at a very detailed level is everything.
