I'd say don't go cheap when buying any type of equipment, especially welding equipment. It will only disappoint you in the end.
If you don't get something that will do the job right, go out and hire the job done, it would actually be cheaper in the long run.
Syncrowave Millers are OK, not the best, but they will do the job, I'd say that would be the minimum quality machine to buy. Miller has their Dynasty machines, 250/350,
that are as good or better than any thing else on the market today, 9K+ for the 350s, but well worth the money. You can fine tune these machines for the materials and conditions as required. Quality machines are required for quality finished welds.
Bottom line, if you buy a cheap machine your wasting your time and money.
Rouse