How long is a piece of string? (Sorry!)
A lot depends on the pedigree (and whites and coloureds will go for different prices). Easiest is to check out preloved to get a ball park figure. At the bottom end (at least round here in West Wales if you take them to market nobody will care what breed they are and they will go for £40 or so - so anything up from there is possible. We have a few whites we are trying to sell and are dropping the price to get some interest. My guess would be that a (registered) shearling might be available for £150 from an unknown breeder (even if it comes from a good bloodline) whereas a top breeder might manage twice that figure. Prices will drop £10-15 per year as the ewe gets older. We almost managed to sell 5 ewes (ranging from 2-8 years old) for an average of £90 but the buyer dropped out at the last moment (grrrr!). Coloired yearlings were going at the Llandovery sale last month for 100-150 guineas (and they were nothing special. A good coloured yearling ewe could easily be twice that.
At the end of the day process can be wildly variable. At Llandovery for example, registrable (i.e. not yet registered) ram lambs were going for 100 guineas or more (and could be completely impotent) whereas towards the end of the Ryeland group we managed to get a 3 year old proven ram with full pedigree paperwork and competition wins in major shows for 100 guineas - nobody else bid! I was more than happy with that
Unregistered will be less. Having said that, Ryelands are seriously competitive (in breeding terms) round here, so in your area they could be very different.
Does that help or add to the confusion?