Definitely Tier 3. If you take the advice of the above stables and are a high demand shop, you could quickly jump to Tier 2

I would price 1-15k depending on cuts and complexity. Start low and get your art out there, if it is popular, raise the prices.

Bay Stable Set: Looks pretty good over all, the horse has nice body shape, but it is very smooth and has no detail or texture. It looks good from a distance but up close, you notice small things, like errors on the bridle

Mare and Foal: The mare looks pretty good, she has a decent body shape, although her front legs kind of faded. The mane and tail have good shape but lake texture and detail. The quality of the mare is quite even. The foal, coloring is cute, but the shape is poor. The cutout job could use soon work. He only has one hind leg and seems to be sinking into the sand. The tail is very smudged and has no shape or texture. The mane is quite good but still lacks texture. The quality isn't super even as the body looks more "animated" or how you would expect a manip to look where the head still looks he same as it would at the beginning.

Paint: The paints body shape is quite poor, it is so smudged, he is blending together. The chest and neck, along with the upper flank and buttocks have strangely good texture compared to the rest of the horse. The mane and tail have no real shape or texture and look more like feathers than hair, despite hat, the horse fits well into the background and there is a nice reflection.

Please, don't let this deter you from continuing your work. I apologise if this brings you down, just want to give you honest critique for you to use to grow and learn.