What is the cost of 1 Robux?

As a keen observer of the digital currency and gaming economy, I'm curious to understand the pricing dynamics of Robux, the virtual currency used in the popular platform Roblox. Could you elaborate on the current cost of 1 Robux? I'm particularly interested in knowing if the price is fixed or if it fluctuates based on market conditions or the demand within the Roblox community. Additionally, I'd like to understand if there are any discounts or promotional offers available for purchasing Robux in bulk or through specific channels. Your insights into this matter would greatly assist me in making informed decisions within the digital gaming economy.