Take home pay
I'll take a stab at giving a straight answer. Yes, the variables are many. It depends on how many tax exemptions you want, what level of benefits you sign up for, etc. The AW payroll is bimonthly. The first and 15th of each month. During each paycheck you are paid half of your "base" salary. Which is half of the 75 hour minimum guarantee. The check on the 1st of the month is only the half month. I have 4 exemptions and got the best health insurance, my take home check after taxes and deductions has been around $900 for that first payroll. On the 15th paycheck, they again pay half of the base then add all of the extra pay you earned from the month before (per diem, extra time above minimum, etc.). My average 15th check has been about $2,600 take home plus or minus. I've been working the 85-90 hour lines and tried to pick up 2-4 days of open flying every month, so my number might be above average. But, I also pay more for better benefits.
The others are correct that there are a lot of variables. During the first few months of training, it was monthly minimum every check. If you sit on reserve and don't fly much, you could be looking at as little as $2,000 a month take home. If you have to commute to base from anywhere, crashpads, hotels, food, and other expenses will eat hard into what little you are bringing home. The bonus offer helps, but you have to be disciplined enough to use it wisely. If you are young, single, and don't need the expensive insurances you can increase these amounts by several hundred dollars a month.