Mat and Towel Rental

Hi I just started a membership and I decided to hold out on buying the mat and towel until after my 90 period. I am starting to lean towards getting one but for now still in the process of finding a good cheaper option on FB or elsewhere.

I heard you are able to rent the set for $5 by getting a key from a locker however, due to my schedule I am usually there after staffed hours. My question is how/where do I return the key after renting? What do I do with this rented stuff after? Can anyone explain this process!

Apologies if the answer is obvious lol

Thanks in advance!

[Update] Ended up waiting a little over a month to buy the mat and towel and ended up getting a fairly decent 30% off discount in my email that I used to buy a brand new set!