I have 2 of these and the rock. Also they are on sale at the moment. Mind you I have the larger 256 meg size. If you can stretch your budget, I would suggest it instead.
http://www.amazon.com/Samsung-Electronics-2-5-Inch-Internal-MZ-7TE120BW/dp/B00E3W15P0/ref=sr_1_3?s=electronics&ie=UTF8&qid=1404922378&sr=1-3&keywords=samsung+840+evo