I bought these for less than $3 ea for 3:http://www.lctech-inc.com/Hardware/Detail.aspx?id=0c3b6f7a-d101-4a60-8b56-3abfb7fd818d
Hardest part was getting the nerve to try them out, worried about 5V vs 3.3V. Next hardest was getting female to male jumpers. After that it was write enough sketch to see the module report back okay with a 2G FAT-formatted SD card in place. Then write enough sketch to prove the rest.
I didn't start by writing extensive code........
I needed both SPI and sdFat libraries (SD library with SPI library works too).