With the worst case scenario that you're running only a single 2gh stick on a host laptop and therefore sucking about 50W at the wall, in an area where there's high high 40c per kilowatt hour rates, then with current exchange rate, you're making only about 40c a day while costing 50c a day to run.
Solutions... i) mine at a slight current loss figuring BTC will top $5000 later this year... ii) put the stick in a machine that's on for other purposes to host... iii) get an old WRT54G router mod it for USB, mod flash larger, install cgminer, run on that for about 10W total consumption (This should be a less than $5 option, sure spend $$ on a Pi instead if you also want to defer your payoff date into the next century)... iv) investigate advantages in time of use pricing, if you get 10c/kwh overnight, only mine overnight! ... v) Run more hashing hardware for better economies of scale
i mine using a 2004 laptop, Compaq v2000 presario. Spec: 1.6ghz single core, windows xp. I run it with full power battery saver while connected to power source. Deactivate all apps that consume cpu. Running at 34 degress celcius and even the cpu fan didnt spin at all because the chip doesnt need it. I doubt it suck 50W but anyway im still a university student. At the moment, electricity bill can be nullified.
Talk about for more hashing, it's okay if i buy another same devices for about 3 to 4 months later (1 pieces) USB ASIC miner? or it's better to do cloud mining? thanks before