Would the harbor freight welders for around 100 bucks or a little more be good for making roof racks. I like the DEPHEP roof rack, and I don't think they are made for the 4Runner and I would like to try to make one.
It's cheap doesn't mean it won't work. Keep the duty cycle and metal thickness in mind and you'll be fine. For the price of a dinner go for it. You buy their extended warranty you can take it back. You'll get some experience and decide if you want to get a proper welder like Hobart, Lincoln or miller if you get hooked on welding. It will be a learning curve to get good welds so be patient.