The cost of things, for perspective, are listed in the PHB but I will give a little here.

An apprentice artesian can reasonably make 1gp per day. A general laborer may earn 20sp a day.

For 20 sp you could eat reasonable hot meals and afford lodging for a day and not much else. That's the indenturer laborer model of economics.

Some thing are very cheap, some are very expensive, that's just supply and demand. Prices are subject to change due to local disruptions and supply shortages.