Expensive is relative. First off like Werhusky said, get to lvl 50 and max rank in your GC. You can blaze through that if that is your primary goal but you won't have enough gil to do anything at the end of that. Get a gathering job going and start mining or botanizing, then hire both your retainers and set them to also be gathering. Grab crystal shards at first as those both sell well and will also be needed if you decide to craft, which is a very good idea since you will probably want to make own furniture. In all reality you should be able to do it in a couple months if you play religiously 3-4 hrs a day (this is an estimate). Not sure how populated your server is but there might not be any plots available now. That may change in the next few months so get busy!