Used air compressor are available for sale on sites such as eBay, Craigslist, Amazon.com or Machinery Trader. Some sites allow users to purchase the compressor directly through the site, while others require all transaction details be worked out by the individual seller and buyer.
Amazon.com and eBay both contain tools for purchasing used air compressors from private retailers with listings on the site, along with options for reading user feedback on the sellers. Alternately, Machinery Trader and Craigslist only allow users to contact buyers, as they are classifieds sites rather than retail sites. Classifieds sites typically don't provide buyers any protection in the event of fraud or scams, so buyers need to be careful when using these sites.