Why is it that after removing any liability, warranties have expressions like "but in any case not more than $1.50"?

If the non-liability works – it works. If not – why would the second part work?

Some jurisdictions do not alow you to disclaim all liabilities or warranties. Thus, you cover that situation by stipulating a price when your EULA dislaimer is not allowed.

Gary is exactly right.

The thing is many jurisdictions have rules against limitations of liability, but those rules are often "open textured". That means they rely on ideas such as "reasonableness" or "fairness". A cautious drafter might worry that any disclaimer will prove to be invalid. In fact its rare to see a disclaimer that is carefully crafted to cover just reasonable limitations - I occasionally draft them, but I have some unusual clients.

More usually one just writes in a series of disclaimers with overlapping scope. In the hope that one or more of them will stick.

In my jurisdiction (England and Wales) there is authority (i.e. case law) that suggests that limiting liability to a particular sum of money that has some rational connection to the contract, eg the price paid, is likely to be reasonable. It is thus a fairly safe disclaimer and very useful.

A similar example - in my own terms and conditions I limit my liability to the total liability insurance I have (as a lawyer) but I also indicate that I am happy to negotiate an increase in that level of insurance. Again courts are generally more favourable to such limitations than a blanket "no liability" limitation.