I'm looking to implement a 'score' for each story, which is a combination of the number of story points and the business value. Value will just be high medium and low, and worth 3, 2 and 1 respectively. One story point will be worth 10, two SPs will be 9, 3SPs worth 8, 5SPs worth 7 etc. Then it's just a multiplication of the two, so a high value one story point item will have a score of 30, a low value 5 point will be 7.
I've looked at a few plugins to do this, the only one I've found that is available for JIRA Cloud is ScriptRunner, but for $300 per month its a bit steep considering I'm only utilising a fraction of what that tool can do! I've also looked for something that can restrict values based on another field, e.g. if you select value of 'Medium', it only shows you 2, 4, 6 ... up to 20. You then enter 5SPs and it further restricts the field so the only option you have is 10, but I couldn't find anything to do this.
Does anyone have any other suggestions?