It really depends on how much you will use it, and what you are working on. And whether you have 220v or 110v and whether you will be welding outside or inside.
I weld a lot of aluminum so i went with water-cooled HTP invertig 221DV. It has a ton of great features for aluminum so it made sense to me. It's not a cheap welder but i have not had any problems with it and i have had it over 10 years.
Water cooler is key if you will be welding long beads. Otherwise you will need to stop when the air-cooled torch gets hot and then re-start.
My dad has an Everlast water cooled TIG machine, it is on the cheaper side price wise, but seems to work fine.
I like my HTP better, the controls are less confusing to me.
If you go on the cheap side price wise, be aware that the torches are often lacking,