Some of the generic drops have become expensive because of consolidation. For example, generic pred forte drops used to be very inexpensive but now there are only two companies that make it and those two companies are owned by the same two large pharmaceuticals that own the branded medicines, hence the price of the generic is almost the same as the expensive branded options. The price of drugs does vary from one pharmacy to another and each insurance plan has its preferred drugs which cost much less for patients depending on the deals they have made with the manufactures. For example brand A might be priced well at one store because they have made a good deal with the manufacturer and made it their preferred drug while brand B would be expensive. Across town a different drug store chain might have a great price for B and a high price for A because they have make B their preferred drug and have a great volume price with the manufacturer.
Alas, it is hard to find a cost effective way to protect your eyes around cataract surgery.