Might sound a bit silly but how long are you intending to be in business?
Multiply that number of years by the annual cost of every software program.
You'll have to be careful because finding all costs can be so challenging that it becomes impossible.
So, "Heads up!"
Vendors who say that their support plans are optional have support plans for a reason: They fully intend to see to it that you pay the annual support fee. How? After purchase and perhaps after the money-back period, calls for help are greeted with 'play time is over. If you didn't enroll in the support plan, you have no support and if that doesn't force you to pay the fee, then software updates (often needed to resolve an issue) will be withheld until you do.'
Web-based software costs are harder to hide or disguise. If the monthly rent isn't paid you get evicted. The elephant in the room is the cost of adding additional users or, although you may not be thinking of expanding just yet - the cost to open a second location. Find out now before getting locked in.