You could get away with a pretty cheap hosting bill, I think a $10 VPC would be more than enough. My current Azure forecast is around $65, but that is for a couple other things too. Half the reason I went big with the different features is that I just started at Microsoft and wanted to learn the different things... plus you get a $150 monthly credit.

All of the capture stuff just runs on a Raspberry Pi.

I believe under 500 transaction a month its free.