If you are in the US the T-Mobile deal from Apple looks solid. $200 back and no contract at all. Can cancel as soon as your rebate arrives.
You'd still need to pay for activation and maybe a month or two service. You'd probably only save $100 or less after everything. My cellphone's with AT&T so I checked out T-Mobile's tablet only postpaid plans. It's $60/mo for both Essentials and Magenta, $75 for Magenta MAX.
Doesn't seem like it's worth all the hassle. I'm happy enough to just use my Amazon Prime rewards and gift cards for the iPad.
Plus, the 12.9 1TB 5G was backordered to July on Apple website when I woke up (6:30) while Amazon still had both colors available for order. I've got hope I can get my Amazon order first half of June.
Side note: It's a good thing this forum has Save Draft. Tab reloaded after I checked out T-Mobile's website for data-only plans.