I wouldn't pay more than $75-100 for the colt unless he's gelded already. If he's gelded, I might pay just a bit more.
If he hasn't been vaccinated at all, then there are a LOT that he has missed, making him at risk. He's missed his first Tetanus Shot, his first EEE (Encepalomyeltis sp?), his first dose of Strangles, and first Rabies shot. If he's 6 months old, he's due for a second shot NOW of all of those as well as his first vaccination for Equine Herpes Virus. I believe that Rabies and EEE are mandatory, at least in your area, and all of the others are a VERY good idea. I'd atleast make sure he gets the strangles of the optional ones though. Its nothing to mess with. If he's 8 month old, he's overdue for his second rounds and never got his 3 month old vaccinations.
I posted that to show you just how much money has not
been spent on him that you will have to spend on him yourself. I have a miniature mule filly who is 7 weeks old, and I've already spent well over $250 in vet bills on her- and I only paid $125 for her in the first place. She's out of two registered, vaccinated, healthy parents too. I'm about to spend another $150 on shots as well, when she is due for her 3 month vaccines, and I even give some of the shots myself. It will likely cost you more than that if your vet has to make a farm call. I trailer mine up to the vet to bring costs down. Gelding him will be another $100-200, depending on your area. Again, some vets let you trailer your horse to them to make it cheaper.
I'm not trying to scare you away from him, honestly. I know what its like to have a horse that you've fallen so much in love with that nothing else matters. I just want you to be aware of the costs that are going to come with having a baby, or any horse for that matter. They're aren't cheap animals unfortunately! XD
I'd try to talk this man down, if I were you. $200 is just rediculous for an unregistered, unvaccinated miniature foal out of a most likely unvaccinated mare. By all means buy him if you think he's the one, but make sure that you go in with your eyes open! Good luck and definitely post pictures when you can!
By the way Punks, that bay mini is ADORABLE. A bit pricey though for a rescue O_o that's almost what I paid for my registered, cart trained, fairly well bred four year old xD granted she's a sourpuss though...you couldnt pay most people to take her!