Building your first SaaS application can be scary. New technology and tools have made it more affordable than ever, but there's still plenty of expenses. And chances are good that you'll grow much slower than you're imagining. Under-estimating expenses and over-estimating revenue is a recipe for disaster. Do what you can to avoid that.
Before you get started, take a quick pass at this worksheet to get an estimate of how much it will really cost to run your application. Make some adjustments and explore different scenarios so you can get an idea of how much money you need in the bank to get your idea off the ground.
Starting & Sustaining by @garrettdimon is solid. If you are starting a new company, it will save you a TON of time. Todd Garland Founder of BuySellAds
…the accompanying spreadsheet has to be seen to be believed. While it's an incredibly useful tool for planning and measuring your business, it's also the most beautifully designed spreadsheet I've ever seen. Wade Winningham Developer at Updrift