Well, I haven't found much in the way of PCMCIA receivers, but I have found plenty of USB and Bluetooth ones.
USB receivers are usually cheaper than those using BT. BT's only real advantage over USB is that it's wireless, but the drawback is it will need its own source of power (ie batteries). USB is wired, but it can be moved around, which is an advantage over PCMCIA. PCMCIA's advantage is it's simple, but you can't very well place your laptop outside your car if your car is blocking reception from a satellite or two.
The cheapest one I've found so far (I've actually bought it and tested it, and it works fine in both Linux and Windows, believe it or not) cost less than $40. The sacrifice for the price is that it's generic and you won't get much manufacturer support in case you aren't sure how to work it, but at least if you get shipped a defective device you should be able to RMA it to the company you bought it from. You'll find the link below.
Whatever you get, make sure it supports NMEA, especially if you're running Linux.
Also, if you don't have any software for interfacing with your GPS, you might want to consider buying a bundle (ie M$ Streets & Trips comes with a USB GPS receiver, but at a hefty price).