msteder,
Are you looking in the red or green area?
CPU states: 0.0% user, 0.1% system, 0.0% nice, 99.8% idle
Mem: 255384K av, 100832K used, 154552K free, 0K shrd, 14816K buff
Swap: 514072K av, 0K used, 514072K free 51804K cached
PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
26567 root 15 0 1092 1092 852 R 0.3 0.4 0:00 top
The red area is total for your whole system. The green is just that process. So here TOP is using 1092 bytes of memory.
You can also try ps aux and it shows you the same thing. free will show you total memory stats.