It depends what you are wanting to do?
if your esablishing a flock, it may be better to buy a ewe with lambs at foot, or wait till autumn and buy draft ewes off the hill and breed yourself?
The last 6-7 years less and less farmers have cades they sell - as its now worth bringing them on yourself, and I know myself, and many others, only sell the weakest / poorest bloodlines out as cades, anything worth keeping for breeding, Or any I can get fat cheaply - IE wean fast or that had good weight on them already, are kept.
As your in wales - Welsh mountain ewes are usually reasonably priced, often in the £30-£50 bracket with 2 seasons left in them - a great start to a flock.