how can i half assley seal a leak

ok i think i found the infamous leak in my AC lines. How can i like just seal it without the expensive stuff. Maybe some silicone? or something?

Unfortunately, you can't really 1/2-A seal it. The working pressures are pretty high and will cause a patch to come out. Depending on what it is, you can do a couple of things. If its an Oring which is typically where the spring-lock fittings hook up, get some new Orings. If its a cracked hose, see about replacing it with a junk yard part. If its the compressor shaft, you can maybe get a new seal to fix it. If its a component such as the condenser or the evaporator, you'll need to replace it.
You could put in a leak sealer, but everything I've ever read about them is that they cause a lot more problems than they cure.