Can't go wrong with Futaba or Sanwa, those are by far the 2 most popular systems in my area. I currently run Graupner, but that system is not in the budget range unfortunately.

Whichever system you choose, I would highly recommend you select a system that offers "Servo Speed" adjustment. Many drivers tend to select a servo that is too fast for their skill level because they are told "get the fastest servo you can afford" but this is some of the worst advice you can get. While I agree that a fast servo is a good idea in general, there comes a point of diminishing return. Most pros in my area will recommend a servo in the .08 to .12 sec/60° range, every driver has a different preference, so instead of buying 10 different servos, it's a lot easier to simply reduce the servo speed through the radio.

I recently tried to help a driver at the club with a Spektrum radio and the servo speed adjustment on it was wonky, to the point where the feature was useless. I personally try to stay far away from Spektrum for many other reasons, but having the ability to tune servo speed is what I feel is the single most important setup adjustment above anything else. It's a fact that slower servos are less likely to strip gears too

If it were me, I'd limit the choices between the MT-S or the 4PLS, both of these systems offer servo speed adjustment for a low budget price.