Where can you buy a ramp to get on to a horse?

you can look on the internet , in magazines , local newpapers etc , there might be a few studs that are in your area that you can contact if you are looking for a certain type of horse , you can even look around riding schools they might have a experianced horse or a horse that might suit your needs , there are many places you can buy horses but i recommend going and seeing the horse"before " you think of buying it
If you're talking about real life you should be completely prepared before buying a horse and you need to know how to look after your horse, if you choose to get one, properly and not cause it any harm.

If you are prepared try looking in cattle markets and animal auctions in your area because they often sell horses. You can check newspapers and horse magazines such as Horse and Hound (and the website) that do private sales of horses. Preloved.com, Horse and Hound, Horsemart, etc. are all good websites to look and find your perfect horse. Good luck! :)