I am blocking megane

My car is locked and I don't know what to do. It's a Renault Megane and it can only be started with the key, but it's broken and there's no way to start it any other way because it locks everything. Please, I urgently need help. I don't know what to do; I need the car. The mechanics who have come to look at it don't know how to handle the problem. They just tell me I have to order another key, but I got a quote and it's very expensive since it has to be ordered from abroad and costs around 400,000 (currency unspecified), which is out of my budget.
Any information would be greatly appreciated.

Look, you can unlock it with a scanner if the problem is that the computer is locked; there wouldn't be a problem. If it's a problem with your key, you'll have to buy one if you don't have both. Or, the other option, at least here in Chile, is that they unlock the keys and their codes, and it works like a normal car. This is done at places where you get keys made, not car dealerships. Try asking; you have nothing to lose. There's another option, but it only works in a handful of cases: disconnect the battery for 30 seconds or a minute and see what happens.

Okay, my friend...
if you want the car to start, it's very easy. Make a duplicate of the car key. It doesn't matter what material it's made of, the important thing is that the cut is exactly the same. Then, when you have the key, if the black part of the key is damaged, where the central locking buttons are, find a way to open it. Very carefully, remove a small black pebble that's pressed into the base of the plastic part of the key.
Then insert the duplicate key, bring the glass you removed close to the start switch, turn the ignition to "on,"
and then start your car. That's it.
What's happening is that your vehicle is equipped with an immobilizer (Renault is very specific with this system and it's classified by letters: A, B, C, D, ... Z, but it always works). Every time you put the key in the ignition, a crystal called a "transponder" transmits a code to the antenna (transciver) that's circular around the start switch. This code changes every time you insert and remove the key, meaning it will only recognize the last code recorded by the transponder. Even if you buy a new key, it won't start because you have to program the key, the immobilizer, and the PCM.
What they do in most cases is leave the car without the immobilizer and insert any old key, which makes your vehicle vulnerable to tampering.

Good luck.