The youngest piece of that site is Twitter bootstrap hails from 2010, so we're really only talking about the last 4 years of your 15+ year career.
The specific technologies that danso mentions are crucial for two reasons.
First, danso probably already has lots of experience with those pieces. Second, those aren't the buzzwords of the month, they're specific technologies that developers choose to use because they're force-multipliers.
Go back 10 years and I'd share your disbelief at the 10-hour time frame for the given task. It would take me at least 10 hours just to figure out where I can host the site! Twitter Bootstrap makes nice-looking design so easy to build, compared to 10 years ago where I'd easily burn hours trying to get the CSS to look right and it'd still end up looking like a programmer made it.
Rails could have several models generated in the same time it takes me to setup PHP to connect to the database.
Stripe's main claim to fame is that Paypal's API sucks. Go skim the Rails guide for Stripe: https://stripe.com/docs/checkout/guides/rails (Paypal's documentation has improved lately though.)
10 hours is not a lot, but leveraging current technologies makes a large portion of this task totally feasible.
OTOH, there's this quote about the underestimation of time required, popularized in 1985 which still rings true today:
"The first 90 percent of the code accounts for the first 90 percent of the development time. The remaining 10 percent of the code accounts for the other 90 percent of the development time."
—Tom Cargill, Bell Labs