With the end of the month rolling over this weekend it is the time when some begin preparing their monthly invoices to bill clients. Theses days there is no shortage of online tools to help with financing and invoices, so we thought we would take the opportunity to point out a few tools to help you get your weekend work done quickly and efficiently. With a plethora of services comes an equally cumbersome amount of features and options, from invoice limits, to pricing and to iPhone apps. Hopefully with this quick overview of four great services you’ll be able to better choose the right one for you.

Editor’s note: This story is part of ReadWriteWeb’s Online Finance series, a weekly three-month-long look at how the Internet is transforming finance. From now until April 15, the annual income tax filing deadline for US readers, we’ll be looking at how finance has evolved, analyzing top Web tools and posting video of our conversations with the people who are shaping the online world of finance. The series is sponsored by OptionsHouse, an online brokerage firm with a professional-grade trading platform and some of the lowest rates in the industry for self-directed investors interested in stock and options trading. OptionsHouse offers free, online virtual trading accounts so investors can try out investment strategies before attempting to trade with real money.
FreshBooks

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By far the online invoicing application with the widest set of features is
. Users can create and manage invoices, track time and expenses, brand their documents, and get paid from clients through any of a number of online payment systems. FreshBooks also offers integration with
, an API for developers looking to integrate the software into a business’ current setup, and an official iPhone application. Half a dozen payment options are available, ranging from a free account with limited number of users and clients, to the highest paid account of $149 per month for 5000 clients and 20 users.
Blinksale
Another great service is Blinksale, which offers an unlimited number of clients, but limits the number of invoices through its various payment plans. Like FreshBooks, users can import clients from Basecamp, but the only online payment option for Blinksale is through PayPal. A few downsides to Blinksale include the lack of a basic free account (they offer a free 30 day trial), and not having an official iPhone app, though a 3rd party developer has produced an application using their API. Blinksale has three pricing plans for $6, $12 and $24 per month.
Ballpark
Ballpark takes a different spin on invoicing by adding the missing link of communication between payers and payees, as well as a bidding and estimate service. With a birds-eye dashboard of your activities, users can tell when their clients view their invoices, and Ballpark’s commenting system makes it easy to clear up any disagreements. The service also compliments its slick user interface with an equally attractive iPhone app and desktop notifier for Mac. Users can get a free account limited to 1 invoice and 3 estimates per month, or they can pony up anywhere between $6 and $99 for more users and invoices.
Billing Boss
Billing Boss is a completely free online invoicing solution for you bootstrappers, but this comes at the expense of being limited to basic features. The site does make up for this with its own iPhone and Google G1 applications and the ability to use PayPal. Users can also import their merchant accounts used on Beanstream, a payment services platform run by Sage, which also provides Billing Boss.
There are dozens of online services that provide help with invoicing, including but certainly not limited to: PayPal, Zoho, Simply Bill, Invotrak, CurdBee and Invoicera. There is sure to be a solution out there to fit any business’ needs.
If you know of some other great services you’d like to share, let us know in the comments.