When I replaced my AC Unit a few years ago I got a good deal online and was able to do most of the install myself, with some help from my father. Installing the Goodman was not that hard to install....just needed help figuring out the right breakers to install.
I weld as a hobby myself and used the cheap $40 helmets for a little while, but one of my friends bought me a Optrel Helmet and I will never go back...I know they are a bit spendy...he said he bought mine for like $450....but I bet you could find it for cheaper