If it was a proper true to type gypsy cob with feather, good conformation and well know bloodlines it could be anything for £2500 to £20,000.
As yours isn't a gypsy cob it would depend of how good her markings and conformation were, her parents competition records, her expected height and amount as bone and her temprement. I would have thought an absolute minimum of £800.
Hmm - seen a few sold at the pony sales and they usually go for between £400 and £600, older ones for more. The sheer fact it's coloured seems to send the price rocketing, the quality of the animal seems to take second place. Astonishing really.
I bred a decent coloured colt from my Gypsy cob (tri coloured) mare, by a bay warmblood, I had people begging me for him, and eventually sold him for 1500 as an 18 mth old, that was 6 years ago... Everything I have seen with half decent conformation even without the 'bloodlines' is going for at least £1000.
Around this way, down south, I think you could ask between £500 to £1000. Ive been keeping an eye out for something similar but a bit bigger on coloured contacts.
Seems to depend a lot of how big they're going to make - I could have bought a yearling for 500, had i wanted something under 14.2. As soon as you hit that 15hh+ mark the price jumps - I couldn't find a single coloured cob to make 15hh+ for under 1500 two years ago when looking.
My boy is a gypsy cob, bought as a 2 year old for £800... now worth at least double, can't believe it !! Not that he's ever going to be sold (poor sod).
I know theres a site called Dragondriving that sells coloured cobs at reasonable prices and sometimes other breeds also,maybe have a look on there,i am sure the average is anywhere from £300,just a thought.