Here are some comments on Winsor & Newton brushes, with typical prices for a size 2 brush
#7 Kolinsky sable £20-68 Obviously an excellent brush but I find them a bit too soft and no matter how careful I am they always seem to wear out on me
Sceptre Gold 11 £5-39 My preferred type, sable/synthetic mixture, a bit more springy and resilient than all sable
Cotman £4-40 A synthetic watercolour brush, about the same or perhaps softer than sable. I have a couple but prefer something springier
University £3-50 This is W&N's budget range, and none the worse for that, synthetic, a bit more springy than sable or Sceptre Gold 11. I have #0 & #00 and they're OK for details, I might try a larger size or a flat
Professional Watercolour Synthetic Sable £5-27 I haven't used any of these, but might try one in the near future. Could be worth trying if you like sable but want something cheaper
So as we might expect, all the synthetic brushes are much cheaper than #7 sable
If you're looking for new brushes, especially if you want something cheaper than all sable, you could buy one of each in the same size, and see how they compare, they're cheap enough
And if you're wondering where to start, you could include a #7 sable, and see if you think the extra cost is worth it.