Ok, not sure whether what I am saying is good or bad for the suggestion, I just want to help this idea in any way I can because it could be genuinely game changing (well, items don't really affect the game much but at least market changing.
If prices were really low the people would buy so many items permanently. This might mean less items on the market because tc isn't being spent on marketable goods but I am not an economist so I don't know.
I feel like perhaps people should only be able to rent from the shop since marketeers would master renting and take all the tc earners/makers (peeps you win tourneys or win in public servers to make new tc rather than just giving it to other players in duels bets or trades) and perhaps increase the rich poor divide in Toribash. The reason this matters is because the rich tend to know that buying from players is cheaper than the shop (tc->shop=tc sunk) so their tc doesn't usually get sunk (I think, again I am not a marketeer). The poor have to get money the hard way since they have less items to market or sell (especially if they rent items rather than buying) and less tc to duel or bet. The poor tend to make tc slowly or to buy it and they also tend to buy from the shop, if the shop was more accessible in terms of price because of renting items this might be even truer.
Basically I think that this is a good way to take tc while not having to give the community anything in return (as in an item to market or sell) and should be reserved for the shop rather than being an option for players who would start to rent out for extremely low prices preventing renting from the shop and the subsequent tc sink.
Does that make sense?