As you work to grow your small business or freelancing, you're probably going to work with an increasing number of clients. While this is a great thing (more clients = more revenue, of course!) it can also means a lot more administrative work.

To keep things organized, and the cash flowing in, you'll need a way to keep track of those many clients and projects, invoice each of them on time, manage your tax obligations and, in some cases, chase down your checks. Put simply: Unless you're a real numbers junkie, the accounting side of your business probably isn't fun.

Fortunately, as the startup and gig economy continues to grow, so do the number of tools available to make small business owners and freelancers' lives easier--and that includes invoicing apps and software. Stay on top of your books--and aim to get paid a lot faster-with one of these five products.

1. Wave

Wave not only offers an easy-to-use suite of professional accounting services, but it also does so for free. With Wave, you can do unlimited income and expense tracking, personalized invoicing in any currency and receipt scanning and recording, and never pay a dime for any of it. If you do want to expand and use the app for credit card processing or ACH bank payments, you can pay per transaction; and if you want to add payroll tax services, you can do so for a monthly base fee plus an additional charge for each employee or independent contractor paid.

2. FreshBooks

For a monthly fee, FreshBooks offers a solid range of handy tools. There's customizable invoicing, expense tracking, and automatic tax calculations; plus the ability to accept online payments from your clients directly through the invoices. If you bill by the hour, FreshBooks also offers a time tracking feature (for you and your team) that allows you to automatically bill for tracked hours. And if you start your projects with estimates or proposals, FreshBooks' tool that transforms those estimates into invoices can save you valuable time and energy.

3. Hello Bonsai

Hello Bonsai is a failry comprehensive monthly subscription product that includes tools for generating and tracking proposals, creating and signing contracts, tracking hours and expenses; as well as creating invoices, automating reminders, and receiving payments directly through the service. If you have clients on retainer, the new recurring payments feature will auto-generate recurring bills as well.

4. QuickBooks

QuickBooks is a tried-and-true name among freelancers and small business owners, and offers a bevy of features for relatively low monthly rates -- especially if you go with the $5/month QuickBooks Self-Employed option. (We use this option at my content marketing company Masthead Media). All QuickBooks plans include handy invoicing, expense, and payment tools; but they largely stand out because of the tax tools, which include features like automatically calculating taxes and sorting expenses into the proper categories for deductions. The Self-Employed plan also includes the option to automatically track mileage, separate business and personal trips, and provides other tools to maximize your Schedule C deductions.

5. Harvest

We also use Harvest at Masthead Media to track and report hours for employees on each project (and review the subsequently generated reports) which is supremely helpful when we have so many different people working on so many different things at once. But the intuitive time and expense tracking features are only part of Harvest's appeal: It also makes it easy to integrate that information into invoices, send automatic reminders to clients, accept online payments and more.