only a few MBs have integrated WiFi or come with a WiFi dongle ... for most MBs you need to get a seperate wifi dongle. most common dongles go into one of your USB slots.
I suggest buying some dongle from the company that your router / wifi station is from.
Ah, ok. I'll be moving back home and using WiFi at my house, but then in a couple of months I'll be heading back to college and using WiFi there, so is there any dongle that's extremely recommended for its value?
Well, i use an AVM Fritz!WLAN, but I don't know if that's available in not-german-speaking-countries ...
a good friend uses a Netgear device which works quite well too.
I'd suggest you to look for a dongle that supports 802.11n and 5GHz ... usually those also support 2,4 GHz networks.
With one of those you'll be set for the next couple of years ...