So... In May while in London, I discovered at Boots (pharmacy) Ibuprofen Gel (Ibuprofen 5%), and before leaving for the U.S. scooped up 4 addtional e50g tubes at Heathrow. I look online for a U.S. source and see that you can buy this exact product for $29.95 plus shipping! I am almost positive I paid £4.49 which currently converts to approximately $7.50 USD.
Well... I shall be shopping at Boots again soon. I have two untouched tubes, which are designated for two of my brothers-in-law who suffer serious joint pain. I've shared two other tubes and am hoarding my own for the time being.