Yeah. For easier reference I'll use the Destrier / Dextrarius which were one of most famous types, although arguably along the lines of mid to top shelf ones. As reflected in game mechanics (1st tier cav) most knights rode on lesser rounceys and coursers. Other formations could do with a inochodnik, or desert horses (badaviae), trotters and sumpter horses would reflect świeropki and szwyrzepicze.
Neither is an actual breed (like a Percheron), and we can assume historical Dextrarius + Courser = ingame warhorses. They could be selected from many breeds, but selected they were. So at young age you'd already have to be spending time training them to the very demanding job (think how hard and expensive it is to train a horse to trot in a fancy way. This horse had to follow commands tired, wounded, with roaring screaming and thunder of gunpowder, with plenty of threats in and out of their field of vision). Some would not qualify, or had to be put down. Training itself had to be performed by, or with constant consultancy of a knight - think of this like taking a regular Porshe 924 and converting it to a rally-ready car.
And then for price, you're selling it to people whos entire life, and possibly lineage and well being of a whole region could depend on the horse not acting like any horse you'll see in your life when struck/frightened/tired. So you have elcapo29 shopping for the same life-saving commodity as an owner of several castles, you're gonna feel that invisible hand of market forming a fist.
This is also why in history as in game, sometimes you just couldn't get a horse and go to a war at all! Edward I in 1282 had to institute a tribute payment for those unable to secure horses for the incoming war. Because at this stage word "miles" varied from a highborn lancer to what we refer to as knight, this was accompanied by minimal annual income of said knight, which amounted to ~10-15kg of pure silver, a really hefty sum already but apparently not enough to afford a warhorse.
In 1297 he specifically asked for less but better equipped riders (a "Knight" in middle ages usually referred to a lance - an independant unit led by the actual knight, with 2-13 accompanying fighters some in similar gear to the knight, some as shooters).
In time, toward XVc, you'll for this reason have less affluent knights referred to as burgmans purely because they could not afford a proper kit (hello tier 1-2 cav)
And again, we're talking about coursers/destrier to fit the general "warhorse" theme, I hope if you'll excuse me not using French Livres as I don't know them, and stay to groschen/grivna. Lets use Prague Hrivna, because it amounts to easier to recalculate ~250g of silver, which could be used to mint ~48-60 silver groschen (they got thinner with time). Right off the bat, regular horse could cost like 12 groschen (1/4th of hrivna) while a courser/destriari would typically run 96-288 groschen, but this we have to recalculate from hryvna/grzyvna - a measure of pure silver, because this was a commodity bought by people who MADE their own money, and prices for it are accordingly recorded in such money prefabricate. So already you can realize this is not a frugal-friendly market.
Most extravagant horses would run to 3k groschen, but this is Bugatti made with filigrine kind of silly overprice. This is clearly a horse for late game PC
But I digress, you've asked a straightforward question, for which we need to compare the above to cost and opportunity to purchase a town. I used this term to differ from a city such as Stettin or Berlin, which could (and often did) openly defy kings they supposedly served if it didn't tickle their fancy and they were independant (so typically Bishop or Hanzeatic cities), and from villages which in official documents are often not listed at all. You'd buy a town of X and surrounding villages - the latter were not listed because they could sometimes be abandoned or established fairly rapidly if you owned or controlled given territory. So J. Gilissen terminology.
Sidenote - even for those HUGE major cities, equivalents of in-game cities, annual income could be like 50 gryvien (late medieval Toruń), so as you can see for this HUGE ass city, they'd have to work TWO years to afford the horse a king got as a gift, or like 5-10 proper Destriers.
Back to topic, how much did buying a regular town run you?
Main thing is that you typically purchased the rights to gather tithe from region defined by that central place. Much like purchasing or being granted "a castle" often meant no physical building, but rather rights for gathering judicial fees.
With that disclaimer, I do have some solid numbers for you:
~1304 Terra Michalovensis was sold with buyback rights for 180 grzywien, that's the areas around Michałów and Brodnica
on this map.
Not much later, teutonic order has purchased Pomerania from Brandenburg at 10k groschen, a strategically critical region equivalent to cluster of 2-3 in-game cities, with dozens of named cities within it.
These are based on kingdoms trading strategically critical territories, I couldn't find right now a price for more reasonable smaller cities deeper inside terrotiry, but I'll try to update this post, I'm pretty sure I can find something when parsing by specific knights.
But with ~90 gryvien for strategically critical town, that could afford you a proper warhorse, but you'd be scrubbing bottom of that (very very high shelf) barrel, and would need to liquidate another 2 towns more for an expensive, but not extravagant Dextrarius.
