Well compare the cost of buying a championship deck for M:tG in single cards and then look at how much you can buy in any of the LCG's. Or look at the cost to buy a championship M:tG deck in singles, and then a LCG deck by buying the entire packaged product. And then remember that with M:tG you get one and only one deck. With the LCG game of your choice you will almost certainly be able to put together multiple decks, and many of them will probably also be tournament worthy.
Any game that you want to keep up with the new hotness is going to require an investment... but there is just no comparing the outlay of cash to play the two games at even a moderately competitive level.