Working as a home-based freelancer takes a lot of toll, especially on your back. Sitting in front of a computer screen for over 10 hours a day, 7 days a week does not help at all. So, a good chair is definitely a must, if there’s anything else you have to invest on, other than your hardware of course, its the chair.
And if you have to invest in getting one that you have to sit on for most of the day, getting a great looking chair is never a bad thing. In fact, getting cool Office Furniture for your home office will definitely give you a really good ambiance to work in.
But if a whole set-up is going to be expensive for you as of the moment, you should at least consider getting a great ergonomic chair. Believe me, it will do wonders for you. Just make sure that you separate your kids from your chair because they will definitely try to take it away from you. I know that for a fact. 
