San Francisco-based healthy food delivery startup Sprig is expanding its hours and coverage area, making meals available to customers on weekends and in new parts of the San Francisco Bay Area. It is also adding an Amazon-Prime like option for heavy users to pay a flat monthly subscription fee for deliveries. Sprig launched a little more than a year ago to offer healthy, easy-to-order meals on demand in San Francisco. Via mobile app, customers chose from a limited menu of food options which would be delivered to them in 20 minutes or less. In addition to fast delivery, Sprig also had the advantage of a relatively low cost, with meals generally priced at $10 or less. Now a year later, Sprig is hoping to get more customers ordering more meals, thanks to expanded hours and an expanded delivery footprint. To start, the company is expanding its delivery hours throughout all of San Francisco to 12 hours a day, 7 days a week. It's serving dinners from 4:00 pm to 10:00 pm every day, and is offering lunch from 10:00 am to 4:00 pm during the week. On weekends, it'll serve brunch from 10:00 am to 4:00 pm. It's also going to offer delivery south of San Francisco. Starting in Palo Alto, Calif., Sprig will begin making deliveries and expanding into nearby towns like Mountain View. Those deliveries will be for dinner only, presumably because it's hoping to catch commuters who work in San Francisco for lunch and then return south for dinner. Whatever the case, the companies hopes that the expansion will prove how its business model can work in other markets, including those which aren't as densely populated as San Francisco. In a phone call, Sprig co-founder Gagan Biyani noted that population density for timely deliveries don't matter as much as the time it takes to travel from one place to another. And, as everyone knows, it's frequently easier to cover ground in a suburban area than in an urban one. Anyway, one final way Sprig is trying to grow its user base and volume of orders: The company is rolling out a flat fee that will allow subscribers to get unlimited deliveries during the month. For $10 each month, customers can order as much Sprig as they want, without having to worry about delivery fees. That's especially important as the company has introduced dynamic delivery pricing. Starting at $2 per delivery, the fee can go up to $6, depending on supply and demand. Now, subscribers won't have to worry about that at all. They'll also be able to cancel at any time... But why would they want to? Perhaps surprisingly, Biyani says that having a flat subscription fee could make the service more efficient. Studies have shown that, since Amazon Prime-like delivery models are more predictable, it's easier to determine how much inventory is needed and where demand will come from. While Sprig has delivered more than 250,000 meals in its first year, the company has a long way to go before its service becomes mainstream. Expanding to new places and offering a new subscription delivery model could help it grow over the next several months.