Inexpensive seat-based subscription billing platform?

I'm looking for a subscription billing platform similar to Memberful that sits on top of Stripe that I can implement into my website but one that allows for seat based pricing.

Memberful lets users choose a plan, pay, and manage their subscription on their own with an overlay (without coding which is really nice). However, it only allows one seat to be paid for at a time.

I'd like to allow users to

1. Sign up for a number of seats at the same time
2. Ideally manage the subscription on their own with a memberful-like overlay (but not as crucial as requirement 1)

It looks like Recurly does this, but it seems quite expensive for a new company.

Are there any services that fit what I'm looking for that don't cost so much and don't require much coding?

Thanks!