Hi Joe,
I posted them directly to the graders (PSA) in California. The cost was $20 US per card. Pretty steep, but that was the cheapest service I could go with for that amount of cards (12). Also, I had to declare that each card would not exceed $500 once graded( a very tricky assessment) or otherwise any card that I declared over that amount would attract a $60 per card price tag. I valued 2 cards at $499 and the rest below that. It was supposed to be a 25 day turnaround but took 3 months due to their backlog. I also paid a mandatory $60 insurance payment ( based on my evaluation of the cards) which covered the cards from their end, back to me. So $300US all up plus $40 AUD getting them there(no insurance).
You can get the cards graded for $8 or cheaper, but you need to submit at least 100 cards or more from my understanding. I believe that is why group submissions are a popular way to do it. There is someone on here who organises it( Nissangtr35) you can look him/her up on here somewhere. I believe there are grading services here in Australia but I doubt they would add value to US sports cards. I could be wrong.
I'd definitely recommend going into a group submission unless you had a very valuable card ($5000 maybe?),then I would probably send it in myself and get it insured both ways.
I'm sure there are lots of members on here who could advise you much better than I can.
Hope that helps.