The biggest challenge, by far, is accounting. No accounting package is fully accessible. The best you're going to get is $1. It has some flaws, but if you bang on it hard enough for long enough, you can make it do everything.

If you travel for business, get the app Mile IQ to log your travels; makes claiming them much much easier. I'd say it's 90 percent accessible, at least on IOS.

Other than that, what tools you need depends a lot on what business you do. I use Google Apps for email/calendar/docs/meetings/file sharing/etc. But I've heard good things about Microsoft's offerings also being accessible.

A Residential house painting business. I don't think I will need any special software just basic tools will do. Thanks for the Recommendations.

I do freelancing, and I find Freshbooks invaluable as a time tracking and invoicing solution. The iOS app is very accessible, and while it isn't free the subscription cost is quite reasonable.

I have a recommendation but it's not free. But I believe it's one of the best $1, especially at the workplace. Reading is one of the most daunting tasks for people who are blind or visually impaired and this $1 is actually a tiny camera that works best when attached to an eyeglasses frame. It reads text from any surface whether it be an email, a product's description or an invoice and converts it to audio and then speaks it to the wearer's ear via built-in speakers discreetly in real time. Thanks to its cutting edge aritificial vision technology people who are blind or visually impaired can achieve increased independence. Also, reading text is not the only awesome feature of this device, it also recognize money notes, colors, products and even people's faces.