New ask Hacker News story: Ask HN: Why don't more services offer “pay as you go” pricing?

Ask HN: Why don't more services offer “pay as you go” pricing?
4 by Shorn | 5 comments on Hacker News.
Was browsing a post for a paid search engine just before - the pricing model was USD $ /mth. I didn't bother to investigate further. There is zero chance I will ever pay for search via subscription. The amount is not the problem - it's the fact of being a recurring subscription. Why don't more services offer a "pay as you go” pricing model? As a customer, I like the "pre-paid" or “top-up” model; where you use a credit card to charge your account with an amount, then the product is charged in a “micro-transaction” pricing structure, like 5c per search or something (the amount isn’t important to this post). But I also don't mind the "post-paid" model where I get a bill at the end of the month that varies with usage. What are the downsides of this from the business perspective? Obviously, usage tracking/billing is more complex and you need to deal with the "excess usage" problem, but I'm wondering about non-obvious stuff like: • the business has varying/unpredictable liability to the customer base • most customers don't actually like it - they want the certainty of a monthly bill - especially fearful of "blowout" bills • customers don't like it because of the perception that the business is incentivized toward inefficiency - e.g. use dark patterns to require the user to do two searches instead of one I have experience as a customer of pay as you go pricing models - and I personally like it for many different reasons. If I wanted to use a “pay as you go” pricing model for my own service - what problems should I be prepared to deal with?