If you want to display HTML like tags, use <code> tags, otherwise they will not show.
Like:
<!--begin tagone--> and <!--end tagone-->
If I understand your questin correct, you want to insert tags in your html files, run them through
a perl script where you repace the tags with the contents from another file.
You will not need to use any database just to replace some part of a file
with some part from another file but if your site is heavily updated by many persons
it may be an advantage to have one.
Using a database from the begining will reduce work for you later, if your site grows and you
realize that you need one.
/brother t0mas