I have a clarke something or other mig welder, and it can be used with either gas or no gas, to change you just change the polarity (swap the leads for earth clamp and torch on the front of the unit) and add a regulator on the back. The good thing about gasless is you can do it in wind. Personally my who project is gonna have to be done out-side as there is no room in my garage, hence being able to weld in wind is a big advantage.
Yes the weld is abit more messy with gassless - but that doesnt mean it doesnt clean up. You have to clean most welds up anyway, so whats the difference?
I have a clarke 100e that i have had for about 16 years, i use the 5kg reels of 0.8 and a pub sized bottle of co2 which i get from my local pub suppliers for £9.98 with the vat, a gauge should be about £15-20 and the co2 gauge will also fit a fire extinguisher but not a argon bottle.
I use my welder very regularly (i welded 2 transit vans for mot last month and am on with another allready this month) and i probably go through a couple of bottles of gas a year, but i do have a habit of leaving the gas on.
Hope this helps Bryan