freight

Forgive my ignorance, after much research im still a bit lost. considering something like this: https://www.adafruit.com/products/498 or, ideally, this: http://www.hardkernel.com/main/products/prdt_info.php?g_code=G141743018597 am i correct in understanding that those both still need a second bit of hardware? could anyone make recommendations for a cheap setup, say under 50usd? like i said, it only need to monitor 2 temps for me, though i could probably find other things to monitor also if there was a recommendation with more screen real estate. thanks!