Here's some online classified resources if you're shopping for an airplane.
Trade-A-Plane [
trade-a-plane.com] has been THE worldwide aviation marketplace since 1937. Their yellow paper no longer comes in the mail, but their online presence is second to none. Google stats show that Trade-A-Plane.com averages over one million sessions per month, comprised of 497,716 users in 238 countries and territories.
Barnstormers [
barnstormers.com] receives more than a million visits and 17 million pageviews from 200 countries every month.
Controller.com [
controller.com] offers easy access to thousands of aircraft for-sale listings, as well as parts, components, and salvage aircraft.
Aero Trader [
aerotrader.com] is a leading aviation site for buyers and sellers. Aero Trader’s inventory includes new and pre-owned airplanes, helicopters, and aviation related products and services.
Aircraft Shopper Online [
aso.com] is another online source for aircraft for sale listings (aircraft classifieds) for all types of aircraft: personal aircraft, corporate aircraft, and transport aircraft.
Aircraft Dealer Network [
findaircraft.com] is an aircraft for sale search engine and trusted online resource. FindAircraft.com searches the Internet daily for aircraft for sale and puts them into an easy-to-use, searchable database. Although the Aircraft Dealer Net is huge, it only shows you some of the ads unless you subscribe, but they have hundreds of free ads too.
And there's
eBay [
ebay.com]. eBay is a crapshoot, but sometimes you will find some very worthwhile planes there. Be wary of unethical sellers and bidders. Don't skip eBay, just be cautious.
Lastly, don't forget to Google "Cessna 150 for sale", there are a bunch of oddball single airplane sites out there, and you might find that needle in a haystack.