I am assuming you are using AMD, and if so, the cheaper one you posted will not work because it is 240pin, you need 184pin. Second, they are both brands I have never heard of, and thus they are crap. Third, best buy is a MAJOR ripoff store, for $76, you could get a dual channel kit of 2x512mb (1gb) RAM, by a reputable brand:
You sound like you won't be overclocking, and if so, getting anything higher than PC3200 would be a waste of money because you would never run it that fast. For example, if you buy a kit of PC4000 RAM, it will still run at PC3200 until you overclock it to 250MHz, and in doing so, you would also have to overclock your CPU.