I Purchased a Stuff Pack

[Breerents]

But it was on a disc and not a download.  I have to insert the disc when I play.  Is this normal?  Because its a little annoying, especially when I shut down and forget to take the disc out.

[Noodles]

Yes, it's normal - the method to start the game depends on what was the latest release, so if the stuff pack is the most recent addition to the series and you purchased it on a disc, you'll need to start the game with that disc. I hear if you register the game at the Sims 3 site and/or Origin, you can use Origin to launch the game without the disc even if you purchased the disc version, but someone else needs to give details (or use search to find them) because I do not use Origin to buy/launch games.

(if you are using mods, the NoCD mod by Twallan @ Nraas is propably the most simple way to avoid using the disc, but for a non-modder there's always the extra hassle of setting up.)

[Ricalynn]

When you register your game whether it's a download or a disc, Origin automatically makes it available for download.   However, in order for it to work this way, you might have to actually uninstall and reinstall the stuff pack (SPs don't take too long to do this actually) so that it registers as a download version and not a disc version.