Now for the customs...
The ones on the left, I actually bought a few pairs of flip flops in Anthem Arizona at Walmart, 0.89c per pair IIRC (actually it was a full 89c, or $0.89 if Billt460 is paying attention).
I had an unfortunate incident walking through a field of goat heads in Albuquerque in the orange set...unfortunately not enough margin of safety with regard to asperity contact (intrusion)
We got to Waikiki, and the whole family bought these "sandals" that had "yoga mat". I scoured the ABC shops for a yoga mat and a box cutter, as I wanted Yoga Mat Sandals, and for not $38US.
Failing badly, I bought superglue and box cutters, and made "flip-flip-flop-flops" by hybridising two pairs of thongs (that's what we call them) into a single, unique pair...family was asleep, and in the morning, I walked them into the Sanuk sandal shop wearing the flip flip flop flops, sitting on their faux washed up boat and advising the sales staff on how to do it. Particularly as the Walmart flip flops had a nylon (my guess) reinforcing ring around the plugs...it all held up.
Pair on the right are a pair of thongs which I liked the tiger motif, but had worn down. No room for a regroove, so I found an appropriately sporty "gator" at the side of the road. Image is everything in footwear, and treadpattern is sexy.
So I peeled the tread off them (hard work), manufactured a clamping jig, and made those using contact adhesive.