the king of all 6v servos is the ko 2143, but the futaba 9450 is also good... a lot of guys are using the futaba 9550 (1/2 sized servo) all of these are over the $100 mark

but all is not lost, plenty of people get by with the higher end hitec servos (i cant remember the numbers but 5265 might be one!) and they are only just over $100