I totally agree, there are NO stupid questions. You certainly can use a standard household light bulb, no need to spend extra $ on a reptile basking bulb. Depending on the temps, you could try a 75 watt or even a 60 watt bulb, be sure to wait about 45 min for the temps to stop rising before getting the final temps. When the basking spot was 120, what was the cool side temp and what wattage bulb, if any, are you using on the cool side now?