You need
http://www.royal-mail.com which is the English Post Office.
The website has price calculators and guides to help you.
Prices are going up soon find the new price using the info here:
http://www.royalmail.com/prices2016
or add on another stamp to your SASE once you've found the current price using the calculator.
I can't help with where to get stamps specifically but try eBay or Amazon.
You can use
any stamps for your SASE. The small/large you see are domestic classifications. Find the value of these stamps and use them on your SASE they are valid.
I always recommend 1st/2nd stamps as no matter how much you buy them for, the current value is the current sale price etc. The values of these after rises can be found using a simple Google search or on the RM website (UK letter up to 100g that is your value)
You need http://www.royal-mail.com which is the English Post Office.
The website has price calculators and guides to help you.
Prices are going up soon find the new price using the info here:
http://www.royalmail.com/prices2016
or add on another stamp to your SASE once you've found the current price using the calculator.
I can't help with where to get stamps specifically but try eBay or Amazon.
You can use [u]any[/u] stamps for your SASE. The small/large you see are domestic classifications. Find the value of these stamps and use them on your SASE they are valid.
I always recommend 1st/2nd stamps as no matter how much you buy them for, the current value is the current sale price etc. The values of these after rises can be found using a simple Google search or on the RM website (UK letter up to 100g that is your value)