secondary car seat

I got to stay home with my baby for 9 months but I just got a job so we can purchase a home hopefully within a year. So now baby is going to stay home with daddy most of the day and the last couple hours of my shift will be with a babysitter. We are going to need another car seat since daddy has to drop baby off, which car seat is good for a secondary car seat? Maybe one that's not so expensive ? My baby is 9 months and currently 30in & 21 pounds..We have the Extend2Fit by Graco in my car.