While it might not seem cost-effective, the speed of killing will usually make up for the zeny cost as you can kill more monsters in the same amount of time.
Like I had mention above, you need at least 4 days to be able to change job.
You can exchange your Valkyrie Coins for this set.
You can continue killing Fabres and Pupas for a chance at their rares.
When they won't come, that is when you start to move.
As a Crusader, you want to lead the Party with your Priest or High Priest following you closely behind.