Playing the new version with the slave market saturation mechanic, and some things feel off. First of all, market saturation isn't going to change based on the MC selling a slave or two. There are, according to the wiki, 156,000 slaves in the city. Assuming that slaves are bought/sold every tens years (probably less than that for pleasure slaves, more than ten for labor slaves), 15,600 slaves are processed every year, at two markets. That's between forty and fifty slaves per market per day. One or two more or less are not going to move any needles.
The mechanic works if the cause of market surpluses and shortages is of sufficient scale, like a bunch of slaves captured in a war or a sudden demand for slaves to build a canal or whatever. But, in that case, the MC (being a slaver of a slaver family) will surely hear about the cause and how long its effects are likely to last. The slaver then knows when to hold slaves for sale later (and buy new slaves at a discount) and when to rush them to market to meet an increased demand. In the game, the MC doesn't know what the market is like until he tries to sell a slave. That's not realistic nor is it fun.
Personally, I think the mechanic is too fiddly to be worth retaining. But, if it is retained, it should be altered so that:
1. Player sales does not affect market conditions
2. The player should know the reasons for, and expected duration of, market shortages and surpluses
3. Market surpluses should lower the price for slaves the MC wants to buy, as well as the price the MC gets for5 slaves he sells (and vice-versa when there are market shortages) and thus
4. Changes in market conditions become a strategic planning issue, not a mere gameplay mechanic.
Also, completely separately, you can buy tendstims for $35 by buying them individually, or $40 if buying in bulk. That is a mistake, no?