This is one deal on the higher end of the price scale but I'd say it's priced fair.
You'll understand why in a minute.
But first: let's get clear who wants to get this deal:

*** If you want to sell monthly subscriptions in an easy way this deal is for you ***

Because that's what they are doing. Enabling you to have your subscriptions done easily and very very flexible.
- you want to manage hundreds of products? Easily done.
- you want to sell only to customers, only to businesses or a mix of the two? You can set that for each indiviudal product AND for businesses you can make it mandatory to check the VAT ID.
- you want to give volume discount, have different prices, easily manage coupons? Check, check and check.
- you NEED to abide GDPR (RODO/DSGVO)? This company is located in germany and the servers as well. If you need to know anything about germans it is that we are efficient and have no humor. So they'll take your business seriously and have done all the work to abide by the highest (and sometimes most frustrating and questionable) legislature on earth. In laymans terms: they have done all the busywork for you so you don't have to.
- you love simplicity? The interface is clean, straightforward and looks like a high-end solution. (It does.)

Let's look into some details:
*Product features
Easily manage subscription payments. Use their self-hosted checkout or implement it into your site. Thorough documentation. CLEAN look.

*Product usefulness
If you want to sell a coaching call, a subscription service, a membership kind of product or anything that has a recurring payment - this deal will get you a great step closer to managing everything finance. Including VAT/taxes which is a pain in the EU. But it also already supports multiple other currencies.

*Product UX
CLEAN. Just clean. Nothing is hidden, everything is logical, you'll find what you are looking for. Even though it is not yet a multi billion enterprise the user interface almost looks like it. It's cleaner than Stripe.

*Use cases in your business
I'm selling a monthly webinar service, where people can tune in. Or think about selling a podcast, doesn't matter. I was thinking about selling my subscription with WordPress + WooCommerce, but I would have to buy WooCommerce Subscriptions which is 199$ per year. With this deal I might not (yet) have the familiar implementation like I do with WooCommerce but I have way more flexibility and can manage subscriptions for ALL my different sites and services in one interface and have a birds eye view of my revenue.
This deal can also replace ThriveCart if all you use it for is to collect payments.

Seriously, consider getting this deal if you want to accept payments and want security, ease of use and having the heavy lifting regarding taxes etc. done for you.

Wanted to write more but there is a character limit. ;)

Disclaimer:
As part of the AppSumo Early Review program Beta, I received this deal for free in exchange for an honest review.