My wife wants to sell a digital product $1-$5/month and I'm having a look for a nice platform that could process it and/or provide the platform for selling it.
Recurly might be what you're looking for. Though Stripe, Braintree, and Paypal all have options for subscription billing.
If you're looking for a more holistic CMS/solution:
Shopify seems popular (I believe they partnered with RecurHub to offer subscription billing). In my opinion SquareSpace offers the nicest designs/templates, but I'm not sure if they let you setup subscriptions or not.
A problem with selling something for so cheap is that the fees will usually eat your margins. Perhaps your wife can sell it for a higher price and package in a few months at a time? This way you'll reduce the number of times you get hit by a flat transaction fee.
Recurly might be what you're looking for. Though Stripe, Braintree, and Paypal all have options for subscription billing.
If you're looking for a more holistic CMS/solution:
Shopify seems popular (I believe they partnered with RecurHub to offer subscription billing). In my opinion SquareSpace offers the nicest designs/templates, but I'm not sure if they let you setup subscriptions or not.