Adding one-time fee to subscription service?

Site URL: https://www.superflycomposting.com/services-sign-up

Hi all,

  I'm starting a food scrap collection business. People will sign up for either a monthly or yearly subscription. However, there is a one-time fee when they first sign up to cover the cost of their supplies. I've not been able how to figure out how to add this to my SquareSpace store. I thought I could add another "item" to my store that they could select, but because it's a subscription there doesn't seem to be a way to add multiple "items" to the cart. I was going to add it as a shipping fee and then remove the fee for renewals, but that is not possible as service subscriptions don't have a shipping option. Any suggestions?

Thanks!

Very interested in this question. Any discoveries to share? 

Thanks! 

See the thread below.