Framed pages when used badly are a scourge (Even though the control panel on VB forums use them). They destroy your SEO and make site navigation a pain with extra unnecessary scroll bars. Even if you don't mind that yourself the simple fact that so many net users detest them should tell you not to use them if you're trying to sell something to the general public.
There's even a I hate frames club!
IHFC
If you are trying to sell something on your site then it's not a very good idea to add elements that annoy so many people.
A no back button script is a bit of JavaScript that prevents you from using your browser's back navigation button effectively locking you in the page. If a site does that to me then I will not give them my business out of principle.