What does "your funds in your own account" mean?

It means dues and event payments land directly in the organization's own Stripe account — kept apart from any other organization's money, and not held by SorrelSites on the way there. SorrelSites charges one flat monthly price for the software; it does not take a cut of the dues or event payments passing through, so what a member pays is what the organization receives, minus only the card processor's normal fee.

The short answer

Some membership tools are free, or close to it, because they take a slice of every payment that passes through — a percentage on top of card processing, on every dues renewal and every ticket sold. That's a real, honest business model, and it's worth knowing whether the tool you're looking at uses it.

How the money moves

A member pays dues or buys a ticket, and the payment lands in the organization's own Stripe account — set up in the organization's own name.
The organization pays its payment processor's ordinary cost, the same rate any business pays to accept a card.
SorrelSites takes no percentage of that payment. What it charges is the flat monthly subscription, published on the pricing page.

The practical difference shows up at the end of the year: an organization on a percentage-fee tool has paid a growing amount as its dues grow, quietly, inside every transaction. An organization on a flat monthly price has paid the same predictable number regardless of how good a year it had.

Not a fee pledge beyond what's published — Stripe's own processing rate is between the organization and Stripe, and it applies no matter which software is on top of it. What "your funds in your own account" promises is that nothing extra is skimmed on the way through.