I second the Steelcase recommendation. They initially cost more than the cheap plastic ones but it's worth it both for how much longer it will last you and just how much more comfortable they are.

You also can customize it to your preferences. Things like flexible arm rests, lumbar support, head support, type of cushion and backing you want (extra soft, breathable micromesh, etc.).

I went with the Series 2 Air as another model to consider but honestly they've got quite a few good options. If the prices are too much right now, watching for sales could help. I bought mine for $490 on sale last year and it's $636 for my config right now at full price. Maybe signing up for their email newsletter would get you notice on sales?