When business started picking up, I incorporated (Ltd in UK) and thought of doing the exact same thing, where I build a simple app to do all the accounting statements. I mean, how hard could it be, right ?<p>Well, that's when I got hold of a Tax accountant and had a really in depth conversation with her about book keeping, financial statements and tax. I came out concluding that there are so many small nitty gritty rules that need to be satisfied (I'm thinking its the same situation in the US).<p>She recommended Sage Instant Account Plus, and while it is by far the least innovative product from an engineering point of view, it does the job and most important of all, it does it right. A good example would be that I need to submit a VAT statement to HMRC (UK's IRS) every quarter. Sage does it in a few clicks, and I can trust that the numbers look correct.<p>Now, Sage does have an import facility. I take 1-2 hours a month to do all my book keeping. Revenue is automated, expenses is not (manual entry). I'm reducing my supplier list and it should come down to a solid 1 hour a month.<p>If you're still compelled to move forward with this. Here is what I would look for:<p>1. An API to automate revenues. I really don't think putting in 1000s of monthly transactions is a good investment of time<p>2. Consulted and signed off by a number of accountants. This brings credibility to your service. I think this is important because I really don't want to be in a position 5 years down the line and owe the tax authorities £££<p>3. Ease of use! Sage is clunky. I can't count the number of times I had to use the "Corrections" facility and ammend/delete incorrect transactions. These are all expenses that I've manually put in, so, part of the blame has to go to me.<p>4. Don't stop at just the 3 sheets (balance, P&L, cash flow). Do add reporting facilities and a way to classify revenues/expenses. Would be good if you'd chuck in ratios as well.<p>These are the big ones for me. Sage sorta does (1). Its definitely (2) as its one of the most trusted accounting apps. Forget Sage on (3) and it does (4) in a really odd and clunky way (you need to put in different account types for different revenue streams and what-nots, uugghh).<p>I would prefer if its something I can run on my own server/desktop. If its a one-off fee, I would see something like £400-£500 a reasonable figure to pay for this.<p>If its an SaaS, I would see anywhere between £10-£20 a month. But there's always the 'trust' issue here.<p>HTH!!