A low fico score can be very costly. A buddy of mine picked up his lifetime dream car, a lexus RX330, yesterday. Since he made the mistake of co-signing a loan for his stepdaughter, and she made two payments late last year, his score is 674. That made his payments, according to the Lexus dealer, $30/month higher. If he had been over 700, he would have saved about $1400 over the 48 month term of the lease.