If it wasn't free... – HeartStar BP Monitor Review

It's just a data base. If you need an app to keep track of your blood pressure, this is just one of many and it doesn't cost anything, so go for it. But of course, you could do the same on a spreadsheet or even use a pen and paper. Not really worth the space on my phone, but it may be what you need...
Review by smooth1js on HeartStar BP Monitor.