I am looking for buy more expansion packs for my sims 3 game, however i'm dissapointed at the prices of the expansion packs, especially the older packs. Will there be any problems with buying expansion packs used?

Yes. You won't be able to register the serial keys to get the EP bonuses from the Store, and some of your limited number of allowed installations will already have been used up.

I'm sorry to sound dumb, but is there a limit to the number of times i can install my ep's? I've had my sims 1 games for years..(and they've been installed on god knows how many different p.c's)... But mainly I bought a couple of mine used, and if I change my computer? Does that effect the games?

However world adventures and generations expansions plus a few of the stuff packs often come up in my local cex, and if you keep an eye out on amazon just after the next expansion comes out the one before it will drop in price slightly, I normally just wait out until they fall to a price I'm willing to pay

It seems some people have been forced to ask EA for a new installation of the game they have already paid for. Silly if you ask me, customer service is obviously not a priority.

Base game, WA, AMB, LN & Seasons all came from the second hand bin, and have been installed/uninstalled several times each so far, none of them have been registered as there is no point, went through all that hassle with TS2 not doing it again with TS3.
Think there might be a limit if your stupid enough to buy through Origin, as they have you by the short and curly's with that method, where as with the discs they can't do bugger all to you.

But isn't there a problem with updating the discs if you do that?

nope, you can patch through the launcher or download the super patch and manually install it.

The limit on Origin is 5. I can't imagine running more than 5 installs at once. AND if for some reason you do, you can de-authorize a machine and it keeps the install, but doesn't let you play it. So you could de-authorize the machines you play the least and have extra installs. Is a limit of 5 really a problem?

On a side note, I recently bought a copy of the base game from an Op-Shop for my Mum that had never been registered. She even got the 1000 sim-points. So it can be worth checking.

So am i right in saying that it will be ok to buy used ex-packs, only i wouldn't be able to activate them on origin (unless the first previous owners didn't either?)

Correct. Just be sure there's some policy from the seller that if the game won't install due to a defect in the DVD (and I actually had 1 SP DVD do that to me bought new on the day of release, but BB exchanged it and the new copy loaded fine) you can get an exchange or credit. As from my personal experience, every once in a while physical media can have a defect even without an obvious gouge on the disc.

Using discs I have never run into a limit, and have used the same key every bleeding time I had to reinstall one of our computers, which since 2009 will have amounted to over ten times for the BG. Buying every expansion new is only necessary if you really care about free Sim Points and preorder content. Windows 7 on the other hand, I had to ring up and get reauthorised after reinstalling it four times on the same laptop - I imagine Origin may be like this. Using up the five installs is entirely plausible, especially for a person who always puts on a fresh install before sending a faulty computer back for repairs. Considering how widely pirated both the OS and the game are regardless, I'm surprised they bother having a limit,

I have noticed or is this just me or is there not many of used sims 3 expansions going around.