not all laundromats offer free detergent. In many laundromats, you typically need to purchase or bring your own detergent to use in the washing machines. Some laundromats may have vending machines where you can buy single-use packets of detergent, or they might have detergent available for purchase at a counter.
However, it's worth noting that laundromats can vary significantly based on location and management policies. Some laundromats might provide complimentary detergent as a perk for using their facilities, but this is not a standard feature in all laundromats.
If you're unsure about the detergent policy at a specific laundromat, it's a good idea to call ahead or check their website for information. Policies may have changed or been updated since my last knowledge update in 2021.