According to my logbook after one year online:

735 hours total, average is a little over 61 hours/month. I sat nearly six months of reserve (and didn't get called out very much at all) to start this year.

During the past 5 full months that I've held a line, I've flown 424 hours, averaging to about 85 hours/month. Our lines are getting better (as is my seniority), so this number should continue to increase until I upgrade. I usually pick up about 7-8 hours out of open time each month to boost the paycheck and flight time a bit.

Take home pay, per diem not included, during lineholding months has been averaging 1100-1200/month. I contribute to my company's 401(k), but I don't have their insurance. When on reserve, made right around $1000/month, including per diem. I'm sure that this is the low end of the spectrum (Great Lakes), but hope this helps.