Below I've listed some ponyplay related products for auction. These are not products I am selling, nor products that I have purchased, so I cannot vouch for quality, shipping, etc. These are merely some items that I've come across (since I scan the auctions every so often looking for cool products for myself) that also seem decently priced (based only on my own experience with similar items) at the time I saw them.
Item number 231660402006: Kaysers/Reactor Hoof Boot UK Size 5 - GBP 229.99 + shipping. The item is in the UK, so double check that they can ship to you if you live in a different country. Great opportunity to get a pair of the Reactor boots if they are the correct size.
Item number 310331339371: Hoof boot-esque - $107.00 + $25 shipping. If you like the style of this boot, check seller's other auctions for additional sizing since each size is a separate listing.
Item number 271756982522: Hoof boot-esque - $89.99 + $12.10 shipping. A knee high boot with a hoof-eqsque look (no heel with the toe on a platform) If you like the style of this boot, check seller's other auctions for additional sizing since each size is a separate listing.
Item number 311273055180: Hoof boot-esque - $21.07 + $29 shipping. An ankle high book for a reasonable price if you like the style.
Item number 311269230195: Pony Play Leather Head Piece - It looks like a trainer type bit gag. The current bit is $27.50 (the buy it now price is $36.00) with free shipping (within the US).
Item number 110512578472: Blond or Black Pony Tail - A butt plug pony play tail made with real horsehair. The color options for the tail are blond or black. The butt plug portion is fairly thin. They are currently being sold for $44.95 with free shipping (within the US).
Item number 311273438518: Bit Gag Trainer Head Harness - A fairly standard rubber bit gag trainer, but the price isn't too bad ($27.50 and free shipping).
Item number 251787905670: Fury Fantasy Pony Play Mask - It looks to be a genuine Fury Fantasy mask (at $900USD + $25 shipping it better be). The mask seems to be in good condition, but it is not stated in the description which model the mask is. I'm guessing that it's the FuryFe (their mid level mask) because it's too expensive to be a minishetty and the description says it's a pony mask (as opposed to Fury's full sized horse mask). Anyway, the item is in Australia, so double check shipping costs before bidding. You may wish to confirm the model as well.