You can bind a snippet to a keystroke.
<snippet>
<content>
<![CDATA[<?php echo ${1:What to echo}; ?>]]>
</content>
<description>Basic echo</description>
</snippet>
Save the above as echo.sublime-snippet in your Packages/User folder then edit Default (OS of your choice here).sublime-keymap and add
{ "keys": ["command+e"], "command": "insert_snippet", "args": {"name": "Packages/User/echo.sublime-snippet" } }
Swap out command-e for any key combination you want to use.
Now, when you hit command & e Sublime will add in
<?php echo ;?>
for you and put the insertion cursor right before the ; for you - you can then start to type in what ever needs echoed.
You can also replace ${1:What to echo}
with $TM_SELECTED_TEXT
and Sublime will wrap the text you've selected with <?php echo
& ;?>
when you highlight text and hit command & e.