ArDrive will tell you how much a file costs before you upload it to the permaweb. All pricing is based on the size of each file. ArDrive will check the size of each file you upload and offer a price for permanent storage in AR, the digital currency associated with the permaweb. You can choose to accept that price or decline it.
A lot of the files you upload will cost only a tenth or hundredth of a cent. It is not until the size of the file gets to be 1 MB that it may cost a penny. Remember: this is the price, not for one month or one year, but for forever.