old sdrams use 128Mbits per chip technology which is expensive whereas the latest ones usually use 256Mbits tech which can significantly reduce the cost but cannot be fully recognized by old style of laptops. for example, the pc100 sdrams in the market are all assembled using 128Mbits chips and a 256MB one usually cost you around 150 dollars. for pc133 sdrams, both techiques may be used. that is the reason why the prices for pc133 vary that much. therefore, before you buy, you must get a clear idea what kind of chips the memory is using and whether it is compatible with your laptop. the best way is to bring your notebook to the store and test the rams there.

about 70-80 dollars. pc133 (using 128Mbits chips) about 130-150 dollars. pc100 about 130-150 dollars.

easily check this using windows. one way to check the ram chip is to unplug it from the laptop and see how many memory chips are soldered. but this may be wrong coz somethimes two chips are combined together (they are longer in shape though).so the best way is to take your computer to sim lim and ask them to test the ram for you. of course, if you don't want to do so, you can always buy the 128 Mbit one since they can be used on all kinds of laptops but the cost may be a lot higher.

btw, for compatibility purpose, kingmax sdrams usually use 128 Mbit chip, so that may be a good choice. many kingston rams use 256Mbit chips. if you wanna buy them, better test first. transcend has both types of rams. you may also go to 'storage studio', a storage device store in sim lim. they have a complete reference listing laptop models diff types of transcend rams support.

good luck!