Limit monthly spend by merchant

I was just reading something about increased subscription charges on Reddit, and it gave me an idea that could be very useful.

The idea would allow you to select a limit per month, per merchant or category

For example, if I want to budget, I could add limit on Supermarkets of £X per month - any changes above that would be declined.

The same can work for online. For example I might say reject charges from Adobe over £12 etc.

Very similar to how works

Related? Maybe more technology wise than theory wise