The most difficult thing for me when deciding on tools for a new adventure is estimating my capacity. As best your able think about the thickness, types of metal, and how often you plan to use your welder. These and even less expensive ones are more than adequate for some applications. Alternatively, you may soon wish that you had more amps or other bells and whistles.
Some things to consider.
How many amps can the electrical service where you think you will be using your welder safely supply (I max out at 60amps based on gauge of wire to my garage, this was a limiting factor for my TIG)?
Do you have 220 capability?
Do you need it portable (do you want a 220v/120v, and bottle size)?
Will you be doing stainless or aluminum (you will need pulse)?
What is the thickness of metals you think you will need to weld (thicker means more amps...)?
Do you have a gas supplier in your area, or are willing to drive to/get deliveries from (usually not a problem, however it may impact size and number of bottles)?
Do you have room to store the unit when not in use? Will it fit where you plan to store it?
Is there a service center in your area that is willing and able to service the welder you are looking at?
Sometimes it is best to save cash a little longer and purchase a larger welder.
Sometimes a larger welder is way over the top and completely unnecessary.
These questions and others don't come with easy answers. However, attempting to get answers may actually be less expensive long term.