re: Best way to build a credit score?

Just say no to the two mortgages with adjustable rates. Your lack of credit history is only part of the problem: the other part is your lack of 20% down payment. Over time, your credit score will improve if you keep using the credit card modestly and paying it off each month--this will be sufficient to build your credit history.

But money in the bank will help your ability to get a fixed rate mortgage at a competitive rate. So save, save, save: you want the needed 20% plus a decent 6-mo emergency cushion. Without those assets on hand, you are a higher risk for any lender.

If there is some thing you actually NEED (not want), like a new fridge, furniture, etc. sold by a vendor offering a 0% financing deal, then buy it and pay it off in the scheduled increments.