1996 Honda Accord aluminum tape to repair leak in A/C tube

The A/C is not working on my car. I attempted to refill the refrigerant. When the pressure got to the top of the "green" (needs filled) range, before it got to the beginning of the "blue" (OK) range, I could see the gas coming out of the small A/C tube. Without looking at the exact problem, my trusted mechanic said that type of repair could cost as much as $700-$800 depending on the tube, length, location, etc. Is there any other option for a less costly repair (other than rolling down the windows!)? Can I use aluminum tape to "seal" the leak?