Gasless MIG means exactly that - no shielding gas. the wire is flux cored so it's the opposite of a normal welding rod - instead of the flux being on the outside (the grey/green powder) the flux is on the inside of the fine wire.
The wire is about 3 times the price of solid wire per roll at BOC prices, but if you go to Bunnings and buy the small rolls, the price is similar, but is also 10% lighter per roll (450g instead of 500g for instance) so it is expensive to weld with, but fine for small projects.
I ran Mig Gasless for years. Personally, I don't like it as the welds are dirty, the process is smoky like ARC and the finish isn't as smooth, but it it easy and convenient. I went to gas about 5 years ago and would never go back.
I keep a small roll of gasless wire in my draw in case I run out of gas and have to finish a job.
Cheap MIG's that are advertised as "gasless" do not have the provision to run gas through the welding torch so they are cheaper. The catch is they can't ever run gas, so if you want to upgrade, you're stuck. I don't see that being a problem for you because the bottle hire cost and ongoing fill costs would be prohibitive, even though for the same amount of weld, welding with gas is cheaper- if you have a small job to do you can buy a $30 roll of flux core wire, but if you are out of gas (and wire) you have to buy a roll of wre for $25 (bunnings prices)and a fill of gass for $70 from BOC then $120/year bottle hire to finish the same job.
If you are chewing 5kg spools, the cost is in favour of gas.
I still say if it can't do the job, Arc isn't cheaper
It's not cheaper if it's not being used.
It's not cheaper if you blow a hole in something important because you were using arc
It's not cheaper if you still want a mig after using it.
come up to my place and weld it yourself with my MIG - then you'd never want an arc.... it's so easy - even I can do it
Steve.
) for the heavier stuff, like spring hangers to 5mm chassis?