Flux core wire?

To answer the original question, I suggest you buy a small bottle of 75/25 gas and a spool of solid core wire. The results are much cleaner, and in my opinion the welds are higher quality. The gauge of wire really depends on what you will be welding. Given the electrical limits of the HF welder, .030 wire is going to be the best compromise for general use. If you are going to do sheet metal repair, then going down to .023 wire is a good idea.
But honestly, try solid core wire with gas... you'll really like the results compared to flux core wire.
Thanks for the advice my welder is not setup to run gas it's a flux core welder I'm not sure how or if I can run gas on it. I know the flux core is messy I knew that when i bought it I'm not worried about it the splatter is nothing a grinder won't take off I'm welding lawn mower decks and outdoor equipment I'm not worried about neatness lol I do want to try it on some body panels just to see if I can I want the out come lol I have access to a stick and mig if I need it but they are both 220 I wanted a 110 I could use around the house that's I why I went with the flux core so far it's working perfect.