Fixing leak in A/C line (aluminum hard line)
 

The other day I was working on a friend's 2000 Saturn LS200 sedan. I fixed his evap problem, and he mentioned the A/C wasn't working. So, we ran to the store, bought a can of R-134a and put it in. Still nothing. We drove it back to my house, popped the hood and I listened. I tracked down the slight hiss and found a leak in one of the low pressure side aluminum hard lines.

My question is, how can I go about repairing this? I know I can replace the whole line for about $80. But, is there a simpler solution? Can I patch it with some goop and a hose clamp or something like that? How much pressure does it need to hold up to? How cold/warm does the low pressure line get?

I'll replace sections of lines going to the rear evaporator, typically susburbans where the labor to replace the assembly is very high, under warranty Gm will pay for the lines, tell ya to cut out what you need and patch it in. The way it's sectioned in isn't unlike replacing a section of brake line.
Short answer, I'd just replace it

When off The low side line will see a pressure in psi roughly equal to the temperature it will see in degrees F. When running it might get near 0F