I would try to get a nice chair, if you spend any time at all sitting on your ass at work.
I literally hate my $15 AR chair from Office Depot, although I haven't replaced it yet. I think it regularly sales for $60, but if I had to do it over again, I wouldn't have bought it. Yes, it's that crappy. The first thing you'll notice is that seat cushion won't last you very long before it's compressed.
And many of the regularly-priced $100ish chairs from Office Depot, OfficeMax, and Staples aren't a whole lot better. You're definitely advised to avoid the cheapest models though.