At the time of this article publication, Boost's fees are as follows:
Monthly fee: $29.95 per month, billing every 30 days from the day you sign up.
Transaction fee: 3.5% + .30 cents for every transaction, which includes merchant fees.
Boost is a preferred partner of Stripe. Payments to Sellers are delivered in 2 business days via direct deposit. All transactions are processed via Stripe and are therefore in one of the most robust and secure environments possible.