I'm planning to buy new radio but I don't know if it's any point to buy radio for 100$.
What's the difference between Futaba 3PL and HK-310?
Is the Futaba's transporder more durable than HK-310's?
I'm concerned about the price of Futaba's transponder - 50$.
Thanks

Futaba 3PL transmitter radio will be of higher quality than the HK, so its more about budget. Both will effectively control your vehicles. There are some differences, backlight, programmability, etc that you need to investigate to understand your needs.

Many people (myself included) have used the Futaba radios with the HK or FlySky receivers with success. If you have multiple models to control, consider using the FlySky receivers. I have done this on my basher vehicles.

Just one little, but crucial, thing to be added to your post in bold below:

Is it worth to pay 100$ fot Futaba when HK 310 is for 50$?

If you want a one-word answer, yes.

And if not one answer?

Perceptibly faster response time would be the main reason. Even the "hacked" Chinese un-brand radios have lag you will notice.

Agree - not knowing his application or skill level response time may or may not be a real issue and worth the extra cost to remedy. If he is running RTR servos, response time will be the least of his concerns.

I'm sure the HK-310 is a perfect fine radio for just having fun driving. I've used inexpensive radios for years that many people turn their nose up to. I used them because of my budget. The receivers for my Airtronics radio were $60. I ended up with about 10 different vehicles and buying a $60 receiver for each, was just too cost prohibitive for me. I was mostly just driving to have fun and some not super serious racing. I doubt for me there was really any difference in terms of being a better driver because I was using a faster radio. Faster servos have a much bigger impact.

The real truth of it is we can tell you a lot of technical things but after driving a vehicle with a better radio you wont go back, I was driving with a cheaper radio back in the day and I am going to date myself here, and a friend let me use his Airtronics m8 it was the best there was on the market at the time, anyways he let me run a race with it, I came off the driver stand and said I would be right back and walked inside and plopped 4-500 bucks on the radio in the hobby shop and never doughted the purchase. a good radio which you can get good entry level from airtronics, futabe and have heard good about the graupners as well, the radio just feels different when you drive feels like you have better control and are more at one with the car, but you have to have a decent servo to go with it.

Hitec 7955tg?
Thanks for answers.