TL;DR: I created a handy thing: https://remybach.github.io/destiny-return-on-investment
It makes use of the awesome http://wastedondestiny.com API to get your number of hours and figures out the value per hour you've gotten based on the costs you put into the fields.
Note: You don't have to use the currency buttons, they just help to pre-fill the fields with release day prices, among a few other things. You can change these values once they've been pre-filled.
Why are there only two currencies?
Quite honestly, I found it quite difficult to come up with the release day prices (it's surprisingly tough to just Google for). Thankfully a couple of you here helped me out with the GBP and USD prices just as a way to get started.
On that note…
If you have the know-how, I have this all up on Github (see below). o/
Alternatively, drop a comment and I'll try to keep up if I can and get the details in.
Other than the release-day prices, I'd also love your help with some currency relevant comparisons so that you can see stuff like (to use one of the GBP examples):
Renting the latest blockbuster for home viewing (streaming) would provide approximately £1.60 worth of entertainment per hour.
More of these would be great!
You can edit the prices.js file and open a PR and I'll have a look at merging it in.
ps: I hope your SOs don't hate me too much for this ?
Edit: I've fixed it so that it includes deleted hours now (my bad).
Edit2: Cripes… made a stupid mistake with the change from the previous edit. Fixed the £/$Infinity bug now.