There is no substitute for proper ergonomics!
You need to be able to change the height of the chair so your thigh gets support from both the chair and the lower leg. The chair also need to support the full thigh all the way to the knee.
The back needs to have a good curve and angle for the workload, so you can lean forward some when writing(pen paper type), lean back when watching youtube and somewhere in the middle for normal computer work - and support the lower back (about opposite side of the belly button) all the time.
Wheels are good so you can vary the distance to the desk slightly.
You also need to have the screen at the right height so you dont have to look up at it but not have to look down so much that you have to support the weight of your head with the neck muscles, you should balance it effortlessly on top of the neck.
Being able to vary the desk height is not required but nifty (I raised my desk using bits of 2x4" lumber)
My chair costs over eur700 new (I bought it slightly used for eur200, which I consider a bargain) but ofcourse it depends on how much time you plan to spend in the chair. Mine is certified to be confortable for 8h, but I realy need a walk after 10h. If you are fit and young you can compensate for a uncomfortable chair (as long as you sit correctly) preferably by taking short breaks and constantly varying your stature.
I know it sounds outrageous but If this chair breaks I would probably not go cheaper than eur200 I would possibly just cry alot and cough up the full eur700 or whatever it costs to replace it. It has survived several of my computers, and probably a few more.
IKEA has som great chairs and some horrible ones (decent chairs eur100 and up)
To your specific problem, maybe you should use a bigger font in your browser so you can see properly? Or use the zoom in the Opera browser (I use that all the time) to get all pages readable from a distance. (I got over a meter between the screen and my nose, that's probably too far)