I'd second (or third, even) that advice to get advice and try instruments before buying if possible.
If your budget is only £200 then one possibility is to gamble on ebay (and you need to know that unless the item was 'not as described' you may have no way to get your money back - there are comments on this on another thread) so 'try before buy is not an option here.
Another alternative is either a shop which has s/h instruments (which you can try before buying) or local private sellers.
Both Colin the Bear and I (and maybe other members, too) have gear4music saxes which we are pleased with, and they often have ex-demo instruments for £200 or less and new tenors were about £260 the last time I looked. They do a very good money back if not satisfied guarantee and have good terms and conditions of sale.
If you go for this (or any mail-order source) do have a good, knowledgeable and experienced saxophonist to check out the instrument - preferably as you unpack it.
Things
can get damaged in transit whoever you buy from (another useful thread on this site!) and a witness (and photographs) is a big help. If it is not up to scratch (!) then you can take it up with the supplier. It isn't 'try before buy' but it is 'money back if not satisfied' - but check out terms and conditions and satisfy yourself first.
Probably most saxophones ( including many top names) are nowadays made in China. If they can make computers and everything else... so check this out:
http://www.shwoodwind.co.uk/Reviews/Ultra_Cheap_horns.htm
Do bear in mind that when the instrument was made has a bearing on quality. Cheap instruments have improved amazingly and competition dictates that year on year improvement is the only way to stay ahead of the game. Read Stephen Howard - thoroughly.
It is possible to get a good playable horn with a good tone within your budget without taking risk if you do your research.
But I reiterate: either try before buy (with an experienced played doing the trying for you) or buy with from a reliable firm who do a no quibble money back or replacement guarantee - and get it checked by the experienced played as you unpack.
A good plan would be to find a local sax teacher, agree to have some lessons (even if a few just to start you off) and ask them to check out your instrument.