I would absolutely recommend 1 of each core set as others have mentioned.
That being said I just wanted to point out that while many have suggested picking up 2 of the original core if you can find at a discount you might actually find new core sets on sale rather than the old ones. I believe both coolstuff and miniatures market had the new core sets marked down to around $20 a pop. Target recently had them marked down too. I wouldn't expect to find many of the old core sets marked down as they just did a restock of those sets recently but not nearly at the same volume produced for the TFA core.
The point about taking advantage of a deal is valid either way, I just think it will be the opposite of what was stated previously.