Unless you have the need for a cash register, POS software maybe overkill. One client didn't use one because the largest part of the business (over
90%) was from the internet w/credit cards. The physical store, with a cash register, didn't do enough business to justify the expense and has closed its door to walk-in business. That business started out on Quicken Basic as a hobby but out grew that and is doing low 6 figures using QuickBooks Pro. It is now doing more each month than it did in its first year.A very small, hip pocket business can get by with some version of Quicken, Money, or even a simple Excel spreadsheet. Another client keeps a simplified book and summarizes it by week and year to date. I double check it using Excel in the same way my mother used the Borum & Pease columnar pads and a calculator.
Whatever, be consistent. Good records can save your butt should the tax man come calling.