you might want to do some shopping you might be surprised how inexpensive a 4ch computer radio is http://www2.towerhobbies.com/cgi-bin...I=LXKJD8**&P=7 here is a example of a futaba radio for 140$ that has 4 model memory it's FM which is becoming the older type but they work as good as any other .
there are some very good and fairly cheap radios,you could even buy a non comp. radio and flt.pack for 120$ http://www2.towerhobbies.com/cgi-bin...gm?CATEGORY=JE and less with the tower discount program they have,you have lots of options with your 100$