TSA locks are often sold at a premium outside the US. TSA combo locks on Amazon.de range from about €8,95 to €18,95.

I would never pay that for a small likelihood. I most often use twist ties, but every so often if I see cheap TSA locks while I am in the US I pick up a few (they go missing about 2x a year while flying within the US so it isn't worth it to me to pay more)

Recently I saw a pack of two for under $4 at a discount store called Tuesday Morning.