I have seen people comment that it ranged anywhere from $54-120 per night on check in. Depends on how many are available, and how many are booked. I have also seen people claim to get free upgrades, but I am sceptical. If you win Miss Temptation for the week you do however get a free upgrade for the rest of the week.
I've booked ahead of time on expedia for ~$30-40 american a night more. But may vary with time of year... etc.
It depends when& which and room your upgrading from too, thats why the discrepancy in price you got ''special room'', garden view, pool view,ocean view, suites ect, then Jaccuzi Garden view, then Jacuzzi Ocean front Suites. A lot of time when you book through a charter you getting the cheapest room possible but you still don't know where