Your number 7 is a British George V two pence orange and it could have been issued any time between around 1912 and 1926 ...it depends on the watermark to find out the date of issue etc.

... A used example like this would only be worth a few pennies even in very good condition. The value depends on condition, watermark, variety (if any). Some collectors are interested in the postmark as well as the stamp and some can be rarer than others.