Hi,
I have the Lincoln 135 which is just a bit bigger then the Weld-Pac 100. I think mine costs a bit more but is still in the realm of "cheap welder".
Lincoln certainly makes a good product, but whether you will be happy with it probably depends on what you want to do with it. If you are trying to weld 1" thick steel, you might want something a little heavier duty. I think the 135 is rated for 5/16", which handles most of what I'm likely to need. I think the 100 was rated for 3/16", which was a light for my needs.
have fun,
sf