I know salt was called the white gold and very valuable in medieval times, but I wondered just HOW MUCH it was worth in 13th century central europe.
Like in a relatable sense, what could a kilo of salt buy you in those times for example
Near salt producing areas, a kilogram of salt might buy you 0.5kg to 1kg of wheat or barley. Away from salt-producing areas, where transport costs, taxation, and price-gouging by monopolists could push prices significantly higher, you could buy 10kg of grain, and perhaps more at some times in some places, with that 1kg of salt. For example, the Venetian salt monopoly led to some customers paying 33 times as much as the salt was originally purchased from the producers for.
Salt being approximately the same price as wheat makes it appear cheap. However, two things need to be kept in mind:
A much higher fraction of income was spent on food - that 1kg of wheat was not cheap.
Salt was used in large quantities, for preserving food (pickling vegetables, salting meat and fish) and dairying (butter and cheese).
The consumption of salt varied with location, due to varying availability of fresh food and the need for preservation. Per capita annual salt usage could be as low as about 5kg, and as high as 35kg. Not all of this would end up in the food actually eaten - some would remain in pickling brine, some salted fish would be soaked to remove excess salt, etc. This high consumption meant that the salt trade was extremely valuable (thus, the Venetian attempts to monopolise it), and where salt was taxed, it could be a valuable source of income.
For more discussion on prices, and for references, see my past answer in https://www.reddit.com/r/AskHistorians/comments/d1qgt6/i_know_that_in_the_middle_ages_salt_was_an/
Before other responses come in, you might be interested in the previous responses related to the value of salt, like this thread by u/Pabst_Blue_Gibbon and myself or this one by u/wotan_weevil referring to late Middle Ages (slightly after 13th century though). In addition, cost of salt in ancient Europe was explored in this thread by u/mormengil and u/XenophonTheAthenian or this one by myself.
Of course, salt could have been made expensive by an extensive taxation, described on an example of a French gabelle here by u/sunagainstgold.