The Canon 100mm f2.8 macro is a superb macro lens, possibly one of the best available, and if coupled with a set of Auto extension tubes would give you an excellent setup.
But I have also got excellent results with a set of Kenko auto extension tubes and a Canon 50mm f1.8 lens.
And I got very good results using two sets of extension tubes on the same lens.
TBH, any EF mount macro or telephoto lens will work on the 200D
Are you looking to buy New or Used ! ?
Image stabilisation isn't necessary all the time, and that applies to all scenarios, not just macro...by definition it helps in low light by allowing a slightly lower shutter speed. It can also be counter productive in some shots. I often use flash with macro, which freezes the action and negates the need for os. I don't use the os on my sigma 150 when I use flash, as I'm usually shooting a moving insect and the extra second that the os needs to stabilise, can miss the shot, so don't worry about whether a lens has os or not, if you don't have it, you won't miss it. A monopod also helps with macro, if a tripod is out of the question.
I am looking to buy used as my budget is about 250 pounds
Look at the Used Members section for lenses as you can pick up a bargin
Image stabilisation isn't necessary all the time, and that applies to all scenarios, not just macro...by definition it helps in low light by allowing a slightly lower shutter speed. It can also be counter productive in some shots. I often use flash with macro, which freezes the action and negates the need for os. I don't use the os on my sigma 150 when I use flash, as I'm usually shooting a moving insect and the extra second that the os needs to stabilise, can miss the shot, so don't worry about whether a lens has os or not, if you don't have it, you won't miss it. A monopod also helps with macro, if a tripod is out of the question.
I wanted to ask aswell is it better to buy Canon EF 100mm F/2.8 or Sigma 105mm f2.8 macro for canon without stabilisation or a Sigma 17-70mm f2.8-4 DC Macro OS which is with stabilisation? Is it better to buy longer lens without stabilisation?
Is it better to buy ... a Sigma 17-70mm f2.8-4 DC Macro OS which is with stabilisation?
The Sigma 17-70mm is a decent lens but it' s consumer zoom, not really a macro. It has a maximum magnification of 1:2.8.... don't get fooled by consumer zoom lenses that have the word 'Macro' painted on them. They'll tend to deliver slightly higher magnification than 'ordinary' lenses, but maybe only 1:3 or so.