Depends on priorities with your goals or motives for kilt-wearing.
If you want to wear the kilt to honor your family heritage, and keep your expenses down, save up for and buy the tartan that best represents your heritage.
If you are looking to obtain more than one kilt because you like to wear kilts, by all means take the "deal" with the universal tartan that anyone can wear anyway!
Will this be your first kilt purchase?