Hi, I came across this discussion while doing a search for "Jersey Pearl". First off, let me say straight away that I am a jeweller )and Jersey Pearl stockist) so you may find my advice helpful. Apologies if you all know this already.
Cultured pearls can come from an oyster or a mussel. Mussel cultured pearls (aka Freshwater) are less expensive. Lately, their shapes have been much improved and now closely resemble the shapes of oyster pearls.
Look for lustre (Jersey Pearl only used pearls with excellent lustre) and avoid pearls with unsightly lumps and bumps. Size plays a part in pricing too; once pearls get too big there is more chance of the oyster/mussel rejecting it so the rarity increases the price.
With your budget you should be able to get a very nice string of freshwater pearls. Personally, I would put most of the money into the pearls and go for a plain clasp - after all, it's worn at the back of the neck and rarely seen.
Length: most useful is lying at the base of the neck so depends on your collar size whether this will be 16" or 18"
Colour: a matter of choice really. Pinkish pearls suit most English complexions, while creams seem to look better on olive based skins.
Ask your jeweller about guarantee of the skins.
Have the pearls knotted on silk; the knots protect the pearls from each other.
I was a bit disappointed that one contributor has found that high street jewellery bump prices up as opposed to online retailers. Our prices, and those of most jewellers I know, have the same prices. I'd think that all Jersey Pearl stockists would be the same.
Pearls need a little extra care to keep them looking their best and hopefully this (very) short guide will be useful www.nicholsonsjewellers.co.uk/news/caring-for-pearl-jewellery/index.html