You can contact Quality Stamps, PO Box 1905, Venice, FL 941 376-5689. They buy US and Worldwide Stamp Collections and travel extensively
An album of old stamps
eBay is a common method of selling old stamps. They can be listed individually or as a set or group. It helps if you can accurately identify the stamps. Check the local directories for stamp dealers in your area. These are commonly referred to as BOB or Back of Book stamps and many collectors specialize in specific types.
you can go to a shop that sells stamps
There are a few websites where an individual can purchase old stamps from Australia. Examples would include Atoncer, Ebay, and Collectible Stamps Collection.
yes. eighteen.
One of the best places to buy old British stamps is online on Ebay. Also the Arthur Ryan & Co. located in Richmond, Surrey is a good shop where you can buy old british stamps.
Yes. All small values 1,2,3,4 and 5 cents are readily available at the Post Office. I am not sure about random values like 11 or 24, but you can put multiple lower denomination stamps if needed.
New Zealand stamps can always be purchased in a New Zealand post office. Stamps, along with rare and old stamps, are also available online from various websites.
One can buy old postage stamps from Turkey from online stamp collection sites. One may also use eBay which offers a plethora of stamps originating from different countries.
ebay
The 5¢ Franklin and 10¢ Washington stamps
Oxfam will take them as will the Salvation army. (http://www.spaceandtimedecluttering.co.uk/page.php?id=4) Most charity shopd will take old stamps.