When you are looking for a software tool to fulfill a specific need, the first place to start is to see if there is not an existing off-the-shelf package that you can buy that will do the job.
By it's nature, a mass produced package will be significantly less costly than a custom developed system purely because the development costs are distributed between thousands or tens of thousands of customers. Therefore, if an existing package can do the job that you need done, go for it; it might well be your best solution.
On the other hand, every business has different needs. Sure, there are things that are the same across all or most businesses: you need accounting software; you need HR software; you need word processors and spreadsheets. For all of those, off-the-shelf is the way to go. But then there are the needs specific to your business or organisation.
Some software venders have huge systems that try and solve many different problems. Such systems are usually very expencive, complicated to configure and maintain, and often needs customisations, in order for them to do what you need them to, which are also very costly.
Our philosophy is completely the opposite to that of the "One system to rule them all". We have found that identifying key areas where custom software systems can make the biggest difference, and focusing on that with targeted development, yields much better return on your investment, and adds true value to the stakeholders.
And we will definitely advise you if the right way to solve a particular problem is to buy an off-the-shelf package.
"There are two ways of constructing a software design. One way is to make it so simple that there are obviously no deficiencies. And the other way is to make it so complicated that there are no obvious deficiencies." - C.A.R. Hoare