Not only can you get a tune without any other mods, but the tune itself is the biggest single mod you can make, the gains from other mods are all much more modest... well they are practically nonexistent without a tune since the stock tune is set up to dumb them down, but even after getting a tune, you will see fairly small power increases from each other thing you do.
Like the tune is an extra 40 hp, and each other mod you do (short of switching to E85... and you'll definitely need a tune for that) is good for about 5-10 hp.
Also, if you're not planning on doing other mods, the "budget tune" will do everything the more expensive full tune will do, for less money. And if you change your mind in the future, you only have to pay the difference in cost between the two to upgrade to full.