Hi BOSScredit,
Leasing is a whole different game than purchasing and I suggest you make sure and do a lot a research before you try to lease a vehicle. There are a lot of factors that go into a lease and not knowing every aspect can cost you money.
First off don't talk about monthly payment whatsoever, they can hide a lot in monthly payments and you will 100% pay more than you should going in there and answering their question of how much can you spend per month. Treat everything as it's own seperate entity, if you are going to have a trade in negotiate the trade in on it's own. Negotiate the price of the vehicle starting at Invoice Price and not MSRP, you can find invoice pricing off of Truecar or Edmunds True Market Value. A good deal will usually be about $500 over invoice but I don't buy domestic vehicles so I would research on some F150 forums what good deals are. Also don't let anyone fool you, you need to negotiate the vehicle as if you were going to purchase it even if you are going to lease. At the end of the day you are paying for the depreciation of the vehicle, which is the residual value, so you want what they are basing their percentages off of to be the lowest they can.
I noticed you didn't have anything posted about what if any type of income you have and saying that you can't afford a new car throws up some red flags. If you are expecting a job and you don't have one yet I would get yourself established before even thinking about purchasing/leasing a car that has a monthly payment.
It is pretty much impossible to give you lease rates as they change monthly. You are going to want to send an email or call the dealership and ask them to give you Residuals and Money Factors for each specific mileage range.
For example, say you're looking for a 3 year/12,000 mile/year lease and they come back with a Residual of 63% and a Money Factor of 0.001875 then we can calculate an estimate based off of that. To find the interest rate based off of the Money Factor you take the number they give you and multiply that by 2400 so: 0.001875 x 2400 = 4.5%. For a Residual of 63% you would be paying 37% of the negotiated price say you bought it at $3000 you would take 30000 x .37 = $11,100.
Now you have your ways to calculate an estimated monthly payment
Capitalized Cost = $30000 which is MSRP minus any discounts
Residual Value = $18900 which is the car's value after the lease is up (in this case 63% of $30000)
Lease Usage = $11100 which is the total amount owed for the lease
Monthly Depreciation = $308.33 which is your lease usage divide by the lease term
Monthly Finance = $91.69 the way that is calculated is adding the Capitalized Cost with the Residual Value and then multiplied by the Money Factor
That would bring you to $400/month for your payment, again the Residual and Money Factor are determined by the finance company and they change every month. That also does not include tax and I don't know because I don't know what state you live in. For example where I live in Texas the auto tax rate is 6.25% and it is calculated off of the total price of the vehicle and not the monthly payment like some states. In California you pay tax off of the monthly payment so it would be $400 x 1.0625 assuming that the rate was 6.25% and that comes out to $425/month. In Texas assuming the 6.25% interest rate you would do ((($30000 x 0.0625) / 36) + $400) which brings it to $452/month. That is what makes leasing a car in Texas (or a few other states) less appealing since you pay the same amount of tax as you would pay if you were buying the car.
A 760 score will help you but the score could be lower since most dealerships will use auto enhanced fico scores that take into account previous auto loan. Since you don't have any if could hurt you but that's not a guarentee. Generally you will get better deals right before new models come out and lease rates typically tend to be best at that time as well.
I really suggest you doing a lot more reading on sites like this http://www.fightingchance.com/auto_leasing.php before you go into the dealership or you will most certainly get taken advantage of. I work at an auto finance company and would be happy to go over any points you might not understand.
