In these days of cloud-based systems, mobile applications, and web-based services, why use a spreadsheet for any other purpose than analysis?

Three reasons: ease, customization, and cost. A spreadsheet can be easily saved, updated, and reused again and again. A good template serves as a head start for you because it can be customized to fit your exact needs and business. And if you're not financially ready (or willing) to invest in a monthly or annual subscription, these  Excel templates will get the job done for your so that you can spend your money on something else that makes you more money -- like good employees or specific technologies.

Now that you're convinced about a spreadsheet's value, are you aware of all the ones that Microsoft offers its Office 365 business users for free? Here are 15 that are worth checking out.

1. Invoices

There are dozens of templates that cater to most businesses, regardless of your industry. All the math is built in and all you have to do is format the one you choose to your liking. These invoices are great to use while on the road and from just about any device. They can also be saved and reused.

2. Price Quotation With Tax Calculation

Like an invoice, many of us give quotes for products and services up front. Sure, there are great stand-alone quoting applications and maybe even your customer relationship management application has this capability. But for something down and dirty, quick to customize, and easy to transport, this template fits the bill.

3. Milestone and Task Project Timeline

Sure, you can subscribe to a great project management application like Asana or Basecamp. But if your project management needs are simple, or if you're not ready to commit to a monthly fee, then just make use of this template. Here you can create milestones and tasks along a visual timeline and then launch scatter charts and other tools.

4. To-Do List for Projects

Want something a little more simplified? Then use this template instead. Here you can itemize each part of a project, along with notes about each task and a place to track percentage complete.

5. Event Budget

I bet, like me, your business conducts events during the year. You do training, you have customer parties, holiday get-togethers, product demos, summer picnics for your employees, or straight sales events. Is this worth it? You're never going to know the real return on investment of these events unless you track your estimated and actual expenses, compared with income, so that you can determine the event's ultimate cost ... or profitability.

6. Total Cost of Ownership Calculator

You want to buy a piece of equipment. Or property. Or a special inventory item. You're pretty sure that you will profit from the investment. But how do you really know? Using this spreadsheet, you can create assumptions that you believe will make the investment worthwhile and then assign units and dollars as measurements. The spreadsheet will take care of all the calculations from there.

7. Simple Loan Calculator and Amortization Table

You'll find lots of quickie loan calculation apps online. But here you can dig down into monthly payments for years to come, try different scenarios and -- most important -- save the spreadsheet to refer to at a later date. This simple loan calculator will create an amortization table and payment schedule for any type of loan. You just input the loan amount, interest rate, loan period and start date, and monthly principal and interest payments and let Excel do the rest.

8. Business Plan Checklist

I'm not a believer in long, complex business plans for a small business. But I am a believer in a business plan -- something short, simple, and easy to understand. Voila! This template lists all the things you should be including in your plan, using the Strength, Weakness, Opportunity, and Threat (SWOT) analysis framework. Then you can use this template to create a checklist of the key activities that need to be performed when you create your plan.

9. Startup Expenses

Probably the most common thing that befalls a would-be entrepreneur is a lack of financial acumen. No, you don't have to be a trained accountant. But it helps -- from day one -- to have a handle on your expenses. Using this spreadsheet, you'll be prompted to consider all the different costs that you'll likely incur and the assumptions you're making. It's a spreadsheet that's instrumental for any startup, particularly if you're looking to raise capital.

10. Net Worth Calculator

Why are you spending so much time working anyway? Is it love? Passion? The desire to make the world a better place? Maybe -- but let's admit that the money is kind of important too. Using the net worth calculator template you can create your own personal financial statement to track how wealthy you're becoming, or just to prove to a potential lender or investor how wealthy you are. Just plug in your assets and liabilities and you're good to go.

11. Buy Versus Lease Calculator

It's the age-old question: Do I buy that new car or lease one? Or should I buy a property or just lease office space? Ask three financial experts and you'll likely get three different answers. But it doesn't have to be this way. You can make the decision based on facts. Just use this spreadsheet (and no, it's not just for cars), plug in your upfront and ongoing costs, and your decision will be made.

12. Weekly Time Sheet

Maybe you're using a payroll or time and billing system that enables your employees to log in their hours on the go. But if you're not there yet, this template does all that for you. It will document regular, overtime, sick, and vacation hours. All totals then get automatically calculated.

13. Mileage Log and Expense Report

There are some awesome travel expense applications -- like Expensify and Concur -- that automatically scan and import airline, hotel, taxi, and meal receipts and then transmit the data to accounting. But there is a cost. And if you have only a few people who are on the road at intermittent times of the year, it's probably good enough to just have them complete a spreadsheet expense report. If that sounds like your situation, then here's your spreadsheet.

14. Small Business Cash Flow Projection

I don't care how passionate you are about your business -- if the cash isn't there, you won't be either. This template is designed for the non-accountant. Just enter all your known inflows and outflows, along with a beginning cash balance from your bank statement and the spreadsheet will roll forward your cash flow into the future. If you see red, then you've been warned.

15. Breakeven Analysis

It's not about breaking even. It's about making profits. But this is a start if you want to at least make sure you're staying in business. It's also a great tool for driving sales because you'll know what revenue number you need to hit to at least cover your nut, and then everything else is profit. Use this spreadsheet to sum up costs, prices, volumes, and other factors that will impact your net profit.

Note: My company, the Marks Group PC, is a Microsoft Partner. I have received no compensation from Microsoft for writing this piece. But I have profited from using some of these templates!