There's much that can be done to upgrade the Super Cub; add ailerons, brushless motor, Lipo batteries, but it'll require an upgrade to the radio system, too.

I would suggest getting the SC and make sure this hobby is the way you want to go since it can get very expensive. Since it flies right out of the box, and some places will even give you an extra battery with the purchase, it will be all you need for a while.

Spare parts (I'm not going to call them repair parts to keep your enthusiasm up) are readily available from your LHS or on line and aren't that expensive.

There are other planes that cost less, but in the long run I'm sure you'll enjoy the SC much better.