Check around for second hand Furniture, Thrift or Office stores. I find that Thrift stores associated with Churches sometimes have better quality stuff at lower prices than Goodwill or Salvation Army.

Then there is always the ever popular Estate Sales.

Here in the US I have found several web sites I can put my zip code into and local sales pop up. Most have pictures and that helps a lot when planing which to visit and in what order.

That isn't a small budget. I wouldn't spend HALF that for a chair.