I found this offer for a Target Circle 360 membership under my Target Circle Deals section. I also received a notification on my phone about it.

This makes the membership free essentially ($100 off of a $99 cost after using the $50 off delivery) but there is an upfront cost of $49.

It does say in the offer that it's for Target Circle card holders. My Target Circle card was very easy to get. Offer is YMMV

https://www.target.com/c/deals/-/N-atb3q


Target Circle Bonus

• Save $100 when you join Target Circle 360™
• Target Circle Card holders, subscribe to a Target Circle 360™ annual membership for $49 (reg. $99) and get $50 off your next $50+ same-day delivery order
• Expires Jul 12

Benefits of Target Circle 360
When you become a Target Circle 360 member, you'll:    

• Get unlimited $35+ Same Day Delivery orders to multiple addresses
• Be able to place same-day orders from dozens of retailers through the Shipt Marketplace   
• Enjoy no-rush returns with an extra 30 days
• Get free 2-day shipping on hundreds of thousands of items

There is a screenshot of my offer attached to this post.