Where to create an Email Subscription button in a small blog?
Put a small box at the sidebar that will be shown on each and every page of your site. Or, you can make a separate page for email subscription and put the anchor link on the homepage and/or in the blog's main navigation.
At the end of each post. Put your button. Telling your users that for updates they must subscribe. Apart from this you can always create a subscription box and put it in the sidebars as suggested earlier.
HTML button form? mailto: