What do other institutions do? At the Pennsylvania Academy of the Fine Arts, the charge for a single adult ticket is a straightforward $15. “We don’t ever bump up our admissions price,” a spokeswoman said.

The Museum of the American Revolution charges $19 for adults, unless it charges $25. The lower price requires visitors to set a time and day for their visit. The museum website notes, however, that the ticket will be good  “at any time after the time you selected. On all but our busiest days, we are happy to honor your ticket at any time on the date you selected.”

The higher-priced ticket allows access at any time. A distinction without a difference? The museum doesn’t think so. “Some days are completely booked,” a spokeswoman said. That additional $6 will get you in. 

The Philadelphia Museum of Art has a straight admission charge of $20 for adults and a pay-what-you-wish policy every Wednesday after 5 p.m. and on the first Sunday of every month. But that does change on occasion.

“The vast majority of our exhibitions are included with general admission,” said a museum spokeswoman. “When we have ticketed special exhibitions, they have been priced at $25 and include general admission.  At present, we do not plan to impose a special exhibition surcharge for the next couple of years.”

And then there is the Franklin Institute. Prospective visitors are advised to take along a calculator to determine prices.

The general admission adult ticket for the institute is a straightforward $23. But if you want to see a special exhibition, like “Terracotta Warriors of the First Emperor,” on view through March 4, it’ll cost you $35 total if you want to go before 5 p.m. After 5, when the rest of the museum is closed, you can see the warriors for $20.

Tack on $6 if you want to go to the IMAX Theater or the Franklin 3D Theater. If you want to go only to the theaters, it’s $10, although the IMAX ticket price varies “for major motion features,” according to the website.