There are a ton of variables that determine price. For instance, if you buy software that requires you to buy their hardware, it costs more. HOWEVER, you typically will run into fewer problems because they require specific hardware. Their support techs support a limited scope of hardware and therefore have worked with your exact model recently. As an example, Freepos allows you to use anything you can find. However, when you’re having issues with printing, there’s a limited amount of support you can expect from such a company – I do NOT speak for Freepos. They can offer generic printer support, but when you start asking very specific questions, you’re going to be referred to the vendor (again, this is not specific to Freepos).
Determine what your actual requirements are. You probably need a requirements list and a “nice to have” list. If the software fails on any single requirement, mark it off the list. You can then start making choices based on cost with the “nice to have” list.
One thing I STRONGLY urge you to do is to buy two of those $100 USB external drives. One stays at your house in a safe at all times. You swap them out daily. Day 1, you backup the system to drive 1. It goes home with you that night and goes in the safe. On day 2, you backup the system to drive 2. It goes home with you and drive 1 comes back to work with you the next day. Why a safe? It’s data… it’s somewhat on the “priceless” side. Why not in your car? If your building catches on fire, your car may not make it away from the building. By the way, two drives is the ABSOLUTE least you want. In addition, not instead of, you may want an online backup service as well.
A good POS system IS your business. It has all of your customers, their orders, your costs of products, your inventory, your sales, and your entire accounting system in it. Every attempt I’ve seen at going “completely paperless” has failed. However, the paper has certainly changed. The notebook is gone, and it’s all printed by your printer. You need a soft copy (a backup) to even attempt to re-assemble your business after a disaster (including something as simple as a computer hard drive crash).
If costs are that tight, perhaps you want to start with hand-written paper and upgrade to a POS system when you can afford it.