How to assemble cash registers with your own hands to sell alcohol with minimal investment?

Question

Payment terminals

Task: to launch an alcohol store with minimal investment.
The main issue is the launch of CCP, in accordance with the law. But it is desirable to get out of the minimum budget.
There is a choice, taking ready-made solutions is convenient, but most often they involve a rigid connection to a certain software with a large subscription fee (for example, for some, in order to simply transfer data to a separately purchased UTM, you have to pay from 500 rubles per month for one cash desk)
In general, as I understand it, the iron binding now goes only to the Fiscal apparatuses and drives.
Eagis can be run even on a vacuum cleaner, which will be used for other purposes (I may be wrong)
Studying our and Chinese Internet, I came to the conclusion that it would be easier to take a separate touch monoblock + the necessary peripherals for each cash register.
But there was one more question, very disturbing me. What kind of software for cash accounting fits the requirements? (Minimum costs + legal compliance)
Thanks in advance for the answers, perhaps I wrote something completely deviating from the truth. It's the first time I'm facing this kind of problem. But it just needs to be done.