Do it yourself?
It is possible to do some of these tasks yourself with a few simple tools such as a heavy duty stapler, screwdriver and claw hammer. Drop in seats or stools are an easy project to make a start on. Take care when removing the old cover as you will be able to use this as a template when cutting out the new upholstery fabric.
Headboards, if they are a straightforward shape, can also be a suitable project for a beginner and you will end up with a unique item that perfectly co-ordinates with your scheme. Top tip - if you are re-upholstering a double or king size headboard choose an upholstery fabric which can run horizontally so that you don't have to join pieces together.
If you are feeling ambitious there are many colleges which run upholstery classes where you will be able to learn to tackle more complicated projects.