Rewrite rules for custom CMS - php

Question

I'm in the process of building a custom CMS for a client and I'm getting stuck on rewrite rules in .htaccess. I'm trying to rewrite anything to page/?pid=xxx -- so, for example, /about becomes page/pid=123.
I assume the problem that I'm having is twofold: I'm building this site in a subdirectory for the time being (/clients/afsb) and I've also got an existing rewrite rule in place to remove the .php from file extensions. Another possible wrinkle is that I'd like to be able to have the rewrite rule ignore any files that actually exist -- for example, the home page is at index.php (or just /, in this case) and I wouldn't want the rule to affect that. Likewise I've got two other pages that are not dynamic (/contact, for example.) Here's what I've tried in .htaccess for the time being:
<Files php.ini>
order allow,deny
deny from all
</Files>
Options +FollowSymLinks
RewriteEngine On
RewriteBase /clients/afsb
# Redirect to remove .php
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^(.*)$ $1.php
# Redirect to "page" for dynamic pages
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule (.*)/$ page?&pid=$1
<Files ~ "\.inc$">
Order allow,deny
Deny from all
</Files>
I'm obviously not too strong with .htaccess or regex in general so I'd appreciate any direction you can give. Thanks!

Answer 1

Figured it out, this is what I needed -- I was missing the caret. Thanks to both for looking into it.
# Redirect to remove .php
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^(.*)$ $1.php
# Redirect to "page" for dynamic pages
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ page?pid=$1 [L]