Save the hundred bucks. It will be a long time before you even get to use SIX channels, let alone seven.

And *IF* the day ever comes that you need a 7th, radios will be much more advanced than they are now, so you'll get a lot more bang for your hundred bucks.

For the record, I have been flying for over 45 years and have never had a plane that I couldn't fly with a 6-channel radio.