I have an office chair I purchased from Staples. It has a high back swivels, rocks and goes up and down. I like the arms as they support my arms when I am doing a lot of sewing. I have my sewing table adjusted to the right height so that my arms are parrallel to the table of my sewing machine. The table also came from STaples and my husband cut the legs down to make it the right size. The only other thing I did was add a donut cushion to the seat as I have serious muscle loss in my postier due to a chronic disease. I have the same kind of set up height wise with my computer. Without those adjustments I would not be able to use either machine for more than a few minutes.
The chair was on sale for less than $100. I consider it a great investment.