Don't buy one online... electronic imports carry heavy tax thingies before they'll let you pick it up
Usually, electronics are what you really want to bring in from home, not buy here. What happened to your sound card, and how tech savvy are you?
I could ask my friend (local) where they sell cheap laptops, but are you looking for netbook type thing or more of a full-fledged desktop replacement... and are you sure it's your soundcard that's broken (goes back to the tech savvy q, i guess... i know a guy who changed 3 cards on his desktop before he realized he'd plugged his speakers into the mic output, for instance) or perhaps it's something software related vs hardware? I'll ask my friend about where you might get it fixed, too (or get the part, again going back to the tech savvy q). Let me know.