How to repair my Air condionter without spending too much money?

Wondering HOW to fix it?

It depends on what's wrong.

Without spending too much money?

That's everybody's favorite whine.

If you want any help from us, you need to identify your vehicle and tell us something about it's symptoms and when they started.

Where is the noise coming from? 

In general, refrigeration logic must be learned thoroughly.  Various mechanical repair methods must be understood.  Extreme cleanliness must be maintained if the A/C system is opened.  If there is a mechanical problem INSIDE the compressor, that caused any kind of metal shrapnel, the entire A/C system must be flushed thoroughly before a replacement compressor is installed.  If the A/C system is opened, a vacuum pump must be used before recharging.  Any lost refrigeration oil must be calculated and replaced.

I always recharge an empty A/C system (as much as possible) with the engine off.  There is a reason for this.

-Engine overhaul mechanic and general automotive mechanic since 1972

-A/C repair since 1980

p.s.  You are asking about an automotive air conditioner?

When it comes to A/C systems in cars, expect to pay big bucks in most cases.

Marry an airconditioner technician. Do the mechanical parts replacement yourself, then have a certified shop evacuate, lubricate, recharge and test it. Can't get cheaper than that.

There are no "cheap" HVAC repairs.  Either it is done right or it is not done at all.  You have to pay for very skilled technicians, $90 an hour plus.  In your case, the compressor is likely shot and it will be advisable to get a new system if the system is fairly old.

Even if it were possible for someone without any training to repair a complex piece of machinery like an air conditioning unit, it isnt possible to offer advice on how to do so based on a layman's description of the problen. Its noisy and not cooling effectively? You might as well tell me its roughly rectangular and made of plastic and metal.

Assuming you have a unitary (non-window) central air conditioner, you would need to go to a trade school to learn how to repair these units. HVAC technicians are highly skilled, and are paid about $90K/year.