One of Mark's favorite quotes (not sure from whom) is, "Don't let the perfect become the enemy of the good".
Yes grass fed is better. Look into options such as meat co-ops, CSA's etc and see if there is any way for you to do some cowpooling.
These can all help bring the cost down to reasonable.
But if it really comes down to it. Eat real whole foods including CAFO meat and you will already be miles ahead of the curve. Stressing about making everything perfect just raises your cortisol levels. You'll be fine.