If you want to know the value of your specific model, information about your variation or have questions about an obscure model, please post your question to the forums at the Model Horse Blab.
Collectively, these people know a whole lot more about model horses than I do!
The values listed on the Ponylagoon are prices that people have paid for these models at online auctions (with a few exceptions). I have only considered models sold as mint, factory mint, near mint and excellent condition.
If you are buying from a store you will most likely pay more. Keep in mind that the stores have already paid the shipping cost for you.
Some people pay more for boxes, many do not. Some Breyer models have come out with registration papers, tack, ribbons, hang tags, etc.. and some people may find that to be important. Do these missing items alter the value? That is only in the opinion of the purchaser.
An important factor affecting a model's value is it's condition. Really scrutinize the model under various bright lights. Models are misrepresented as mint all of the time, while many hardcore collectors will tell you that they have never seen a truly mint model. Most models come out of the box less than mint, with paint overspray, rubs, paint bubbles or misshapen ears, hooves, etc... A better description would be "factory mint", meaning it has not acquired any scratches, marks or even those little shiny surface marks that can only be caught in the correct lighting condition. A model without these minor flaws can be considered LSQ (live show quality).
Many models gain small white rubs on their hooves, ear tips and tail tips. A model with only these can be considered PSQ (picture show quality) or of display quality. If there are minor detractions from it's purity, it could still be worth a lot and considered near mint. Otherwise it is thought of as being in great, good, or poor condition. What this all boils down to is that models are worth however much someone is willing to pay for them, and the values listed on the Ponylagoon are intended only as a guide.
There are as many opinions as there are model horse collectors but here is a rough guide:
5/5 - mint (extremely rare)
5/5 - factory mint (only some minor factory flaws, most brand new models have these)
4.5/5 - near mint (no distracting flaws, possible minor flaw)
4/5 - excellent (multiple minor rubs)
3/5 - great (multiple rubs)
2/5 - good (several large rubs and or scratches, white areas turning yellow)
1/5 - poor (very yellowed white areas, bent legs, many battle scars, chipped ears, etc...)
0/5 - for remake (gloss or paint added, broken leg, tail etc...)