I got Jaden when he was a year and a half, he was a former show dog that didn't like to show so his owners sold him. He looks just like a puppy and has bonded with me so incredibly fast! He follows me everywhere and loves being here. This is now his home and he knows that. I don't think 7 months is too old, they are still quite young and I am sure they will form a bond with you once he or she gets to know you. Some dogs are more cuddlers than others so it might depend on their personality too, some are naturally more independent and others just want to be with someone all the time.
If they are AKC registered with champion bloodlines 800.00 isn't too high of a price depending on their weight. It thay are really large yorkies then yes but if they are 3-4 pounds I'd say no. Jaden is AKC registered with 67 champions in his bloodline and his asking price was 4,500!
Best of luck to you with your new furbaby!!