@HappyEarl which weight loss medication were you thinking of?
As others have said the Monj website is good for looking at the current prices for Mounjaro, and has links to other sites that do the same for the Wegovy injections, Wegovy tablets or the Foundayo tablets.
As a new customer, most pharmacies will do you a big discount on your first month's order. After that, you pay the ordinary retail price, unless you change to another pharmacy and get their new customer discount. It's easy to change pharmacy.
The Monj site shows which pharmacies operate a subscription service. Most don't, I have never used a subscription one as they tend to be more expensive. Because I don't use a subscription, I only get charged for the next prescription when I actually decide to re-order myself, no automatic charging.
These are the pharmacies that are subscription based, taken from the Monj website today
Bolt Pharmacy, Curely, e-Surgery, Everwell, Get A Drip, Get Weightloss, Happen, Juniper, L'vae, Medicspot, Medy, Numan, Second Nature, Skin & Shape, The Care Pharmacy, The Family Chemist, Trim, Voy
So, if you are concerned about automatic payments going out each month you could avoid those ones.