A free trial is only as useful as how realistically you actually use it. Clicking through menus for ten minutes tells you almost nothing about whether a system will hold up during an actual busy Saturday.
Enter your real product catalog, not a few test items
Adding your full, actual inventory (or a meaningfully large subset) surfaces problems a handful of test products never would — awkward categories, missing fields, whatever doesn't map cleanly to your business.
Run it during an actual busy period, if you can
A quiet trial run tells you the interface looks fine. Using it during genuine rush hours tells you whether it's actually fast enough and reliable enough under real pressure — the only test that really matters.
Test the specific features you know you'll need
If staff access, multi-location support, or a specific report format matters to your business, test that specific feature directly during the trial rather than assuming it works the way you'd expect.
Involve whoever will actually use it day to day
If an owner tests a system alone but a cashier or manager will use it daily, get their hands-on feedback too — the person actually using the till has a very different perspective than the person deciding whether to buy it.
Check what happens after the trial ends, before it ends
Understand exactly what stays accessible on the free tier versus what requires payment, so the transition isn't a surprise — a clear picture upfront avoids a scramble right when the trial period runs out.