Except you missplelled "rares" in the thread title...
As for rares, they vary in cost quite a bit. Some go for over 1.6k/t others for as low as 200+/t. Search for the rares thread to see which are where and how much they cost.
It's actually very simple to do indeed.If that was that simple, it would be already done I think.
Switch your modules to grade D, which can reduce your ship's mass by several tons and increase your jump range by a couple LY. Then upgrade your FSD to C or B if that doesn't do it.
I'm also sometimes getting a message saying "Jump exceeds the maximum fuel usage of 2 tons" and I don't know what that's about. Fuel tank is 16 tons total, and is almost full, so I have no clue why that message appears and my jump is canceled.