I'd say the most reasonable figure to use for that estimate would be current market rates. I can concoct scenarios where the price goes up, but none of them strike me as particularly plausible. And, of course, a hypothetical worst case will quickly wind up with "it's impossible to do cryopreservation on that scale."

For a more reasonable bad-case, I would assume that a prompt cryopreservation is essential, that the whole body must be preserved for revival to be possible, and that legal issues prevent any form of cryopreservation before a legally pronounced death. As such, it's essential to retain the current ridiculous amounts of standby labor that goes in to modern pricing - otherwise thousands of lives are lost any time the system gets flooded by a disaster, and anyone who dies outside an urban area is just plain out of luck.

Furthermore, Alcor and CI rely heavily on volunteer labor, often paid well below market rates. Let's assume that even though medical equipment is tightly regulated and has a lot of expenses related to testing and certification, there's still some economies of scale that cryopreservation benefits from. I'd say that even in a bad-case scenario, it's unlikely (but not impossible!) for this to offset the increased labor charges.

The current market rate for CI is $88K if you want standby and transportation services. Alcor charges $200K for the same service. Call it maybe $100K per person.

$100K * 150,000 people/day * 365 days/year = $5,475,000,000,000 (~5.5 trillion), or about 10% of the world GDP.

If we instead use Alcor's current market rate of $200K per person, you're looking at 20% of the world GDP instead.

Honestly, probably one of the worst-but-plausible cases is simply "cryopreservation continues to require legal declaration of death", since then you never reap the reduction in other medical expenses - if you can cryo-preserve the terminally ill and those who are wasting away, you get some huge societal reductions in medical costs to offset these expenses.

I'd also consider it likely that, no matter what, funeral costs will be vastly lower, which will probably save you a decent chunk of the cost of cryopreservation in wealthier countries. The US spent $15 billion on funerals, but I don't know how well this maps to the rest of the world. I think one could probably reasonably assume at least $100 billion in savings, as it's fairly cheap to throw a cryo-preservation party compared to a funeral or cremation. When you're looking at $5,500 billion, this is not a terribly significant savings, alas :)