Obviously, I know that this is a buyers support thread, but Id love to add my sellers story...
We had a lovely welsh A for sale a few years ago. She was a great first pony, safe, sound, had come from a riding school so she knew everything, and looked after her rider like a pro. Her only fault was that when being groomed, she would sometimes try and groom you back and youd get a little nip.
We advertised her on Horsequest and H&H.
We had three viewers in a row.
The first brought her 4yo, who could barely stay upright in her riding hat, couldnt ride at all, and had to be held by the leg to keep her on the pony. She wanted the pony so that she could take her DD hunting!!!! This was october, so she wasnt talking next winter, or in a few months, but straight away! 
The second brought her slightly older kid to try the pony. This kid was a pony club kicker! She constantly walloped the pony with her heels, yanked on the reins, hit her with a stick and complained when the poor beast switched off! And to the ponies credit, she didnt buck her off and stomp on her, she just ignored the horrid little monster! The mother then had the flipping cheek to tell me that she was looking for something a little more lively! So just to piss her off, we put DD, 9, on, she trotted, cantered and jumped her over a 2ft jump like a dream!
The third was a vet, who tried to tell me that the pony was lame, (because her kid was on the wrong leg, the wrong diagonal and managed to make the pony disunited,) and tried to half the price!
We finally sold her to a lovely family, who came, tried her, got a nip whilst groming and laughed it off, asked Dfriend for riding advice, had a little lesson, hacked up the lane, fell in love with her, and then confessed resignedly that they could only afford 2/3 of the asking price. They were so sweet, and obviously loved the pony, so we let them have her.
Selling can be just as much of a minefield as buying!